Textile printing

ABSTRACT

In an example of a textile printing method, a thermally curable ink composition is applied on a fabric substrate. The thermally curable ink composition includes from about 1 wt % active to about 6 wt % active of a pigment that absorbs ultraviolet radiation, infrared radiation, or a combination thereof, based on a total weight of the thermally curable ink composition; from about 2 wt % active to about 20 wt % active of a polymeric binder, based on the total weight of the thermally curable ink composition; and an aqueous ink vehicle. In the method, the pigment of the thermally curable ink composition is selectively heated on the fabric substrate by exposing the fabric substrate to an emission wavelength from a narrow wavelength light source for a total exposure time of 3 seconds or less. The selective heating thermally fixes the pigment to the fabric substrate.

BACKGROUND

Textile printing methods often include rotary and/or flat-screen printing. Traditional analog printing typically involves the creation of a plate or a screen, i.e., an actual physical image from which ink is transferred to the textile. Both rotary and flat screen printing have great volume throughput capacity, but also have limitations on the maximum image size that can be printed. For large images, pattern repeats are used. Conversely, digital inkjet printing enables greater flexibility in the printing process, where images of any desirable size can be printed immediately from an electronic image without pattern repeats. Inkjet printers are gaining acceptance for digital textile printing. Inkjet printing is a non-impact printing method that utilizes electronic signals to control and direct droplets or a stream of ink to be deposited on media.

BRIEF DESCRIPTION OF THE DRAWINGS

Features of examples of the present disclosure will become apparent by reference to the following detailed description and drawings.

FIG. 1 is a flow diagram illustrating an example of a printing method;

FIG. 2 is a flow diagram illustrating an example of a printing method;

FIGS. 3A and 3B are schematic diagram of different examples of a printing system disclosed herein;

FIG. 4 depicts black and white reproductions of originally colored photographs of control, example, and comparative black ink print swaths on cotton after washing;

FIG. 5 depicts black and white reproductions of originally colored photographs of control, example, and comparative cyan ink print swaths on cotton after washing;

FIG. 6 depicts black and white reproductions of originally colored photographs of control, example, and comparative black ink print swaths on nylon after washing;

FIG. 7 depicts black and white reproductions of originally colored photographs of control, example, and comparative cyan ink print swaths on nylon after washing;

FIG. 8 is a graph depicting the change in optical density (delta (A) OD) for the control, example, and comparative black and cyan ink print swaths;

FIG. 9 is a schematic illustration of a print and different exposure regions that was used in Example 2;

FIG. 10A depicts black and white reproductions of originally colored photographs of first example inks printed on cotton both before and after washing, where each print included a control region (untreated control) and an example region (treated with 395 nm UV LED);

FIG. 10B depicts black and white reproductions of originally colored photographs of the first example inks printed on cotton both before and after washing, where each comparative print was treated with a heat press;

FIG. 11A depicts black and white reproductions of originally colored photographs of second example inks printed on cotton both before and after washing, where each print included a control region (untreated control) and an example region (treated with 395 nm UV LED);

FIG. 11B depicts black and white reproductions of originally colored photographs of the second example inks printed on cotton both before and after washing, where each comparative print was treated with a heat press;

FIG. 12A depicts black and white reproductions of originally colored photographs of third example inks printed on cotton both before and after washing, where each print included a control region (untreated control) and an example region (treated with 395 nm UV LED); and

FIG. 12B depicts black and white reproductions of originally colored photographs of the third example inks printed on cotton both before and after washing, where each comparative print was treated with a heat press.

DETAILED DESCRIPTION

The textile market is a major industry, and printing on textiles, such as cotton, polyester, etc., has been evolving to include digital printing methods. However, the vast majority of textile printing (≥95%) is still performed by analog methods, such as screen printing. Multi-color printing with analog screen printing involves the use of a separate screen for each color that is to be included in the print, and each color is applied separately (with its corresponding screen). In contrast, digital inkjet printing can generate many colors by mixing basic colors in desired locations on the textile, and thus avoids the limitations of analog screen printing.

When inks are digitally printed on textiles, they are exposed to heating in order to dry the ink and fix the ink colorant to the fabric. Some heating techniques involve relatively long exposure times (e.g., several minutes) at lower temperatures in order to avoid burning or other deleterious effects. This can prolong the overall printing process. Other heating techniques utilize ultraviolet (UV) curing, which involves exposure to ultraviolet light to initiate a photochemical reaction that generates a crosslinked network. When UV curing is used, the ink or other liquid used in printing includes a photoinitiator to initiate the photochemical reaction. This adds additional components to the overall printing process.

In the examples disclosed herein, a thermally curable ink composition is coupled with rapid thermal curing by a narrow wavelength light source. The thermally curable ink composition disclosed herein does not undergo a photochemical reaction (and thus does not include a photoinitiator) when exposed to the UV and/or IR radiation. Rather, the pigment in the ink absorbs the UV and/or IR radiation, and as a result, is heated. Because heating occurs through the pigment's absorption of the UV and/or IR radiation, the heating is selective, i.e., ink printed areas of the textile are heated, while non-printed areas of the textile remain unheated. Heating, and thus pigment fixation to the textile substrate, occur with 3 seconds or less of UV and/or IR exposure.

It has been found that the combination of the thermally curable ink composition and the rapid thermal curing generates prints having a desirable optical density and washfastness. “Washfastness,” as used herein, refers to the ability of a print on a fabric to retain its color after being exposed to washing. Washfastness can be measured in terms of ΔE. The term “ΔE,” as used herein, refers to the change in the L*a*b* values of a color (e.g., cyan, magenta, yellow, black, red, green, blue, white) after washing. ΔE can be calculated by different equations, such as the CIEDE1976 color-difference formula and the CIEDE2000 color-difference formula, both of which are set forth in the Examples section herein.

Throughout this disclosure, a weight percentage that is referred to as “wt % active” refers to the loading of an active component of a dispersion or other formulation that is present in the thermally curable ink composition or a pre-treatment composition. For example, the pigment may be present in a water-based formulation (e.g., a stock solution or dispersion) before being incorporated into the ink composition. In this example, the wt % actives of the pigment accounts for the loading (as a weight percent) of the pigment that is present in the ink composition, and does not account for the weight of the other components (e.g., water, etc.) that are present in the formulation with the pigment. The term “wt %,” without the term actives, refers to either i) the loading (in the pre-treatment or thermally curable ink composition) of a 100% active component that does not include other non-active components therein, or ii) the loading (in the pre-treatment or ink composition) of a material or component that is used “as is” and thus the wt % accounts for both active and non-active components.

Thermally Curable Inkjet Ink

The thermally curable inkjet ink includes from about 1 wt % active to about 6 wt % active of a pigment that absorbs ultraviolet radiation, infrared radiation, or a combination thereof, based on a total weight of the thermally curable ink composition; from about 2 wt % active to about 20 wt % active of a polymeric binder, based on the total weight of the thermally curable ink composition; and an aqueous ink vehicle.

UV and/or IR Absorbing Pigments

The pigment that is included in the thermally curable inkjet ink is capable of absorbing ultraviolet radiation having a wavelength ranging from about 10 nm to about 400 nm, infrared radiation having a wavelength ranging from about 760 nm to about 1 mm, or both ultraviolet and infrared radiation.

Carbon black is an example of a black UV and IR absorbing pigment. Examples of suitable UV absorbing blue or cyan organic pigments include C.I. Pigment Blue 1, C.I. Pigment Blue 2, C.I. Pigment Blue 3, C.I. Pigment Blue 15, Pigment Blue 15:3, C.I. Pigment Blue 15:4, C.I. Pigment Blue 16, C.I. Pigment Blue 18, C.I. Pigment Blue 22, C.I. Pigment Blue 25, C.I. Pigment Blue 60, C.I. Pigment Blue 65, C.I. Pigment Blue 66, C.I. Vat Blue 4, and C.I. Vat Blue 60. Examples of suitable UV absorbing magenta, red, or violet pigments include C.I. Pigment Red 1, C.I. Pigment Red 2, C.I. Pigment Red 3, C.I. Pigment Red 4, C.I. Pigment Red 5, C.I. Pigment Red 6, C.I. Pigment Red 7, C.I. Pigment Red 8, C.I. Pigment Red 9, C.I. Pigment Red 10, C.I. Pigment Red 11, C.I. Pigment Red 12, C.I. Pigment Red 14, C.I. Pigment Red 15, C.I. Pigment Red 16, C.I. Pigment Red 17, C.I. Pigment Red 18, C.I. Pigment Red 19, C.I. Pigment Red 21, C.I. Pigment Red 22, C.I. Pigment Red 23, C.I. Pigment Red 30, C.I. Pigment Red 31, C.I. Pigment Red 32, C.I. Pigment Red 37, C.I. Pigment Red 38, C.I. Pigment Red 40, C.I. Pigment Red 41, C.I. Pigment Red 42, C.I. Pigment Red 48(Ca), C.I. Pigment Red 48(Mn), C.I. Pigment Red 57(Ca), C.I. Pigment Red 57:1, C.I. Pigment Red 88, C.I. Pigment Red 112, C.I. Pigment Red 114, C.I. Pigment Red 122, C.I. Pigment Red 123, C.I. Pigment Red 144, C.I. Pigment Red 146, C.I. Pigment Red 149, C.I. Pigment Red 150, C.I. Pigment Red 166, C.I. Pigment Red 168, C.I. Pigment Red 170, C.I. Pigment Red 171, C.I. Pigment Red 175, C.I. Pigment Red 176, C.I. Pigment Red 177, C.I. Pigment Red 178, C.I. Pigment Red 179, C.I. Pigment Red 184, C.I. Pigment Red 185, C.I. Pigment Red 187, C.I. Pigment Red 202, C.I. Pigment Red 209, C.I. Pigment Red 219, C.I. Pigment Red 224, C.I. Pigment Red 245, C.I. Pigment Red 286, C.I. Pigment Violet 19, C.I. Pigment Violet 23, C.I. Pigment Violet 32, C.I. Pigment Violet 33, C.I. Pigment Violet 36, C.I. Pigment Violet 38, C.I. Pigment Violet 43, C.I. Pigment Violet 50 and any co-crystal of quinacridone pigments. Examples of suitable UV absorbing yellow pigments include C.I. Pigment Yellow 1, C.I. Pigment Yellow 2, C.I. Pigment Yellow 3, C.I. Pigment Yellow 4, C.I. Pigment Yellow 5, C.I. Pigment Yellow 6, C.I. Pigment Yellow 7, C.I. Pigment Yellow 10, C.I. Pigment Yellow 11, C.I. Pigment Yellow 12, C.I. Pigment Yellow 13, C.I. Pigment Yellow 14, C.I. Pigment Yellow 16, C.I. Pigment Yellow 17, C.I. Pigment Yellow 24, C.I. Pigment Yellow 34, C.I. Pigment Yellow 35, C.I. Pigment Yellow 37, C.I. Pigment Yellow 53, C.I. Pigment Yellow 55, C.I. Pigment Yellow 65, C.I. Pigment Yellow 73, C.I. Pigment Yellow 74, C.I. Pigment Yellow 75, C.I. Pigment Yellow 77, C.I. Pigment Yellow 81, C.I. Pigment Yellow 83, C.I. Pigment Yellow 93, C.I. Pigment Yellow 94, C.I. Pigment Yellow 95, C.I. Pigment Yellow 97, C.I. Pigment Yellow 98, C.I. Pigment Yellow 99, C.I. Pigment Yellow 108, C.I. Pigment Yellow 109, C.I. Pigment Yellow 110, C.I. Pigment Yellow 113, C.I. Pigment Yellow 114, C.I. Pigment Yellow 117, C.I. Pigment Yellow 120, C.I. Pigment Yellow 122, C.I. Pigment Yellow 124, C.I. Pigment Yellow 128, C.I. Pigment Yellow 129, C.I. Pigment Yellow 133, C.I. Pigment Yellow 138, C.I. Pigment Yellow 139, C.I. Pigment Yellow 147, C.I. Pigment Yellow 151, C.I. Pigment Yellow 153, C.I. Pigment Yellow 154, C.I. Pigment Yellow 155, C.I. Pigment Yellow 167, C.I. Pigment Yellow 172, C.I. Pigment Yellow 180, C.I. Pigment Yellow 185, and C.I. Pigment Yellow 213.

Solid pigments may be incorporated into the aqueous ink vehicle, or they may be part of a pigment dispersion that is incorporated into the aqueous ink vehicle. The pigment dispersion may include a pigment and a separate dispersant, or may include a self-dispersed pigment. Whether separately dispersed or self-dispersed, the pigment can be any of a number of primary or secondary colors, or black or white. As specific examples, the pigment may be any color, including, as examples, a cyan pigment, a magenta pigment, a yellow pigment, a black pigment, a violet pigment, a green pigment, a brown pigment, an orange pigment, a purple pigment, a white pigment, or combinations thereof.

In an example, the pigment is present in the thermally curable inkjet ink in an amount ranging from about 1 wt % active to about 6 wt % active of the total weight of the thermally curable inkjet ink. In another example, the pigment is present in the thermally curable inkjet ink in an amount ranging from about 1.5 wt % active to about 4 wt % active of the total weight of the thermally curable inkjet ink.

For the pigment dispersions disclosed herein, it is to be understood that the pigment and separate dispersant or the self-dispersed pigment (prior to being incorporated into the inkjet formulation), may be dispersed in water alone or in combination with an additional water soluble or water miscible co-solvent, such as 2-pyrrolidone, 1-(2-hydroxyethyl)-2-pyrrolidone, glycerol, 2-methyl-1,3-propanediol, 1,2-butane diol, diethylene glycol, triethylene glycol, tetraethylene glycol, or a combination thereof. It is to be understood however, that the liquid components of the pigment dispersion become part of the aqueous ink vehicle in the thermally curable inkjet ink.

Polymeric Binder

The thermally curable inkjet ink also includes a polymeric binder. Examples of the polymeric binder are selected from the group consisting of a polyester-polyurethane binder, a polyether-polyurethane binder, a polycarbonate-polyurethane binder, and a latex binder. In other example, hybrids of any of these binders may be used.

In an example, the thermally curable inkjet ink includes the polyester-polyurethane binder. In an example, the polyester-polyurethane binder is a sulfonated polyester-polyurethane binder. The sulfonated polyester-polyurethane binder can include diaminesulfonate groups. In an example, the polyester-polyurethane binder is a sulfonated polyester-polyurethane binder, and is one of: i) an aliphatic compound including multiple saturated carbon chain portions ranging from C₄ to C₁₀ in length, and that is devoid of an aromatic moiety, or ii) an aromatic compound including an aromatic moiety and multiple saturated carbon chain portions ranging from C₄ to C₁₀ in length.

In one example, the sulfonated polyester-polyurethane binder can be anionic. In further detail, the sulfonated polyester-polyurethane binder can also be aliphatic, including saturated carbon chains as part of the polymer backbone or as a side-chain thereof, e.g., C₂ to C₁₀, C₃ to C₈, or C₃ to C₆ alkyl. These polyester-polyurethane binders can be described as “alkyl” or “aliphatic” because these carbon chains are saturated and because they are devoid of aromatic moieties. An example of an anionic aliphatic polyester-polyurethane binder that can be used is IMPRANIL® DLN-SD (CAS #375390-41-3; Mw 45,000 Mw; Acid Number 5.2; Tg −47° C.; Melting Point 175-200° C.) from Covestro. Example components used to prepare the IMPRANIL® DLN-SD or other similar anionic aliphatic polyester-polyurethane binders can include pentyl glycols (e.g., neopentyl glycol); C₄ to C₁₀ alkyldiol (e.g., hexane-1,6-diol); C₄ to C₁₀ alkyl dicarboxylic acids (e.g., adipic acid); C₄ to C₁₀ alkyl diisocyanates (e.g., hexamethylene diisocyanate (HDI)); diamine sulfonic acids (e.g., 1-[(2-aminoethyl)amino]-ethanesulfonic acid); etc.

Alternatively, the sulfonated polyester-polyurethane binder can be aromatic (or include an aromatic moiety) and can include aliphatic chains. An example of an aromatic polyester-polyurethane binder that can be used is DISPERCOLL® U42 (CAS #157352-07-3). Example components used to prepare the DISPERCOLL® U42 or other similar aromatic polyester-polyurethane binders can include aromatic dicarboxylic acids, e.g., phthalic acid; C₄ to C₁₀ alkyl dialcohols (e.g., hexane-1,6-diol); C₄ to C₁₀ alkyl diisocyanates (e.g., hexamethylene diisocyanate (HDI)); diamine sulfonic acids (e.g., 1-[(2-aminoethyl)amino]-ethanesulfonic acid); etc.

Other types of polyester-polyurethanes can also be used, including IMPRANIL® DL 1380, which can be somewhat more difficult to jet from thermal inkjet printheads compared to IMPRANIL® DLN-SD and DISPERCOLL® U42, but still can be acceptably jetted in some examples, and can also provide acceptable washfastness results on a variety of fabric types.

The polyester-polyurethane binders disclosed herein may have a weight average molecular weight (Mw, g/mol) ranging from about 20,000 to about 300,000. As examples, the weight average molecular weight can range from about 50,000 to about 500,000, from about 100,000 to about 400,000, or from about 150,000 to about 300,000.

The polyester-polyurethane binders disclosed herein may have an acid number that ranges from about 1 mg/g KOH to about 50 mg/g KOH. For this binder, the term “acid number” refers to the mass of potassium hydroxide (KOH) in milligrams that is used to neutralize one gram of the sulfonated polyester-polyurethane binder. To determine this acid number, a known amount of a sample of the polyester-polyurethane binder may be dispersed in water and the aqueous dispersion may be titrated with a polyelectrolyte titrant of a known concentration. In this example, a current detector for colloidal charge measurement may be used. An example of a current detector is the MUtek PCD-05 Smart Particle Charge Detector (available from BTG). The current detector measures colloidal substances in an aqueous sample by detecting the streaming potential as the sample is titrated with the polyelectrolyte titrant to the point of zero charge. An example of a suitable polyelectrolyte titrant is poly(diallyldimethylammonium chloride) (i.e., PolyDADMAC).

As examples, the acid number of the sulfonated polyester-polyurethane binder can range from about 1 mg KOH/g to about 200 mg KOH/g, from about 2 mg KOH/g to about 100 mg KOH/g, or from about 3 mg KOH/g to about 50 mg KOH/g.

In an example of the thermally curable inkjet ink, the polyester-polyurethane binder has a weight average molecular weight (g/mol) ranging from about 20,000 to about 300,000 and an acid number ranging from about 1 mg KOH/g to about 50 mg KOH/g.

The average particle size of the polyester-polyurethane binders disclosed herein may range from about 20 nm to about 500 nm. As examples, the sulfonated polyester-polyurethane binder can have an average particle size ranging from about 20 nm to about 500 nm, from about 50 nm to about 350 nm, or from about 100 nm to about 250 nm. The particle size of any solids herein, including the average particle size of the dispersed polymer binder, can be determined using a NANOTRAC® Wave device, from Microtrac, e.g., NANOTRAC® Wave II or NANOTRAC® 150, etc, which measures particles size using dynamic light scattering. Average particle size can be determined using particle size distribution data generated by the NANOTRAC® Wave device.

Other examples of the thermally curable inkjet ink include a polyether-polyurethane binder. Examples of polyether-polyurethanes that may be used include IMPRANIL® LP DSB 1069, IMPRANIL® DLE, IMPRANIL® DAH, or IMPRANIL® DL 1116 (Covestro (Germany)); or HYDRAN® WLS-201 or HYDRAN® WLS-201K (DIC Corp. (Japan)); or TAKELAC® W-6061T or TAKELAC® WS-6021 (Mitsui (Japan)).

Still other examples of the thermally curable inkjet ink include a polycarbonate-polyurethane binder. Examples of polycarbonate-polyurethanes that may be used as the polymeric binder include IMPRANIL® DLC-F or IMPRANIL® DL 2077 (Covestro (Germany)); or HYDRAN® WLS-213 (DIC Corp. (Japan)); or TAKELAC® W-6110 (Mitsui (Japan)).

In still other examples, the thermally curable inkjet ink includes a latex polymer binder. The term “latex polymer” generally refers to any dispersed polymer prepared from acrylate and/or methacrylate monomers, including an aromatic (meth)acrylate monomer that results in aromatic (meth)acrylate moieties as part of the latex. In an example, the latex polymer may be devoid of styrene. In some examples, the latex particles can include a single heteropolymer that is homogenously copolymerized. In another example, a multi-phase latex polymer can be prepared that includes a first heteropolymer and a second heteropolymer. The two heteropolymers can be physically separated in the latex particles, such as in a core-shell configuration, a two-hemisphere configuration, smaller spheres of one phase distributed in a larger sphere of the other phase, interlocking strands of the two phases, and so on. If a two-phase polymer, the first heteropolymer phase can be polymerized from two or more aliphatic (meth)acrylate ester monomers or two or more aliphatic (meth)acrylamide monomers. The second heteropolymer phase can be polymerized from a cycloaliphatic monomer, such as a cycloaliphatic (meth)acrylate monomer or a cycloaliphatic (meth)acrylamide monomer. The first or second heteropolymer phase can include the aromatic (meth)acrylate monomer, e.g., phenyl, benzyl, naphthyl, etc. In one example, the aromatic (meth)acrylate monomer can be a phenoxylalkyl (meth)acrylate that forms a phenoxylalkyl (meth)acrylate moiety within the latex polymer, e.g. phenoxylether, phenoxylpropyl, etc. The second heteropolymer phase can have a higher T_(g) than the first heteropolymer phase in one example. The first heteropolymer composition may be considered a soft polymer composition and the second heteropolymers composition may be considered a hard polymer composition. If a two-phase heteropolymer, the first heteropolymer composition can be present in the latex polymer in an amount ranging from about 15 wt % to about 70 wt % of a total weight of the polymer particle, and the second heteropolymer composition can be present in an amount ranging from about 30 wt % to about 85 wt % of the total weight of the polymer particle. In other examples, the first heteropolymer composition can be present in an amount ranging from about 30 wt % to about 40 wt % of a total weight of the polymer particle, and the second heteropolymer composition can be present in an amount ranging from about 60 wt % to about 70 wt % of the total weight of the polymer particle.

In more general terms, whether there is a single heteropolymer phase, or there are multiple heteropolymer phases, heteropolymer(s) or copolymer(s) can include a number of various types of copolymerized monomers, including aliphatic(meth)acrylate ester monomers, such as linear or branched aliphatic (meth)acrylate monomers, cycloaliphatic (meth)acrylate ester monomers, or aromatic monomers. However, in accordance with the present disclosure, the aromatic monomer(s) selected for use can include an aromatic (meth)acrylate monomer. To be clear, reference to an “aromatic (meth)acrylate” does not include the copolymerization of two different monomers copolymerized together into a common polymer, e.g., styrene and methyl methacrylate. Rather, the term “aromatic (meth)acrylate” refers to a single aromatic monomer that is functionalized by an acrylate, methacrylate, acrylic acid, or methacrylic acid, etc.

The weight average molecular weight (g/mol) of the latex polymer can be from 50,000 to 500,000, for example. The acid number of the latex polymer can be from 2 mg KOH/g to 40 mg KOH/g, from 2 mg KOH/g to 30 mg KOH/g, or 3 mg KOH/g to 26 mg KOH/g, or 4 mg KOH/g to 20 mg KOH/g, for example.

The latex polymer can be in acid form, such as in the form of a polymer with (meth)acrylic acid surface groups, or may be in its salt form, such as in the form of a polymer with poly(meth)acrylate groups.

In an example, any of the polyurethane-based polymeric binders may be present in the thermally curable inkjet ink in a total amount ranging from about 2 wt % active to about 15 wt % active of the total weight of the thermally curable inkjet ink. In another example, the latex polymer can be present in the thermally curable inkjet ink at a relatively high concentration, e.g., from 5 wt % active to 20 wt % active, from 6 wt % active to 15 wt % active, or from 7 wt % active to 12 wt % active, for example.

The polymeric binder (prior to being incorporated into the thermally curable inkjet ink) may be dispersed in water alone or in combination with an additional water soluble or water miscible co-solvent, such as those described for the pigment dispersion. It is to be understood however, that the liquid components of the binder dispersion become part of the aqueous liquid vehicle in the thermally curable inkjet ink.

Wax

Some examples of the thermally curable inkjet ink also include a wax. Examples of suitable waxes include those that are commercially available from Lubrizol, such as LIQUILUBE™ 411, LIQUILUBE™ 405, LIQUILUBE™ 488, LIQUILUBE™ 443, and LIQUILUBE™ 454; from Michelman, such as ME80825, ME48040, ME98040M1, ME61335, ME90842, ME91240, and ML160; from Keim-Additec, such as ULTRALUBE® E-521/20, ULTRALUBE® E-7093, ULTRALUBE® 7095/1, ULTRALUBE® E-8046, ULTRALUBE® E-502V, and ULTRALUBE® E-842N, or from BYK, such as AQUACER® 2650, AQUACER® 507, AQUACER® 533, AQUACER® 515, AQUACER® 537, AQUASLIP™ 671, and AQUASLIP™ 942.

In an example, the wax may be present in the thermally curable inkjet ink in a total amount ranging from greater than 0 wt % active to about 1.5 wt % active of the total weight of the thermally curable inkjet ink. Other examples of the thermally curable inkjet ink do not include the wax.

Aqueous Ink Vehicle

In addition to the pigment and the polymeric binder, the thermally curable inkjet ink includes the aqueous ink vehicle.

As used herein, the term “aqueous ink vehicle” may refer to the liquid fluid with which the pigment (dispersion) and polymeric binder are mixed to form a thermal or a piezoelectric inkjet ink(s). A wide variety of vehicles may be used with the inkjet ink(s) of the present disclosure. The vehicle may include a co-solvent, an anti-kogation agent, an anti-decel agent, a surfactant, a biocide, a chelating agent, a pH adjuster, or combinations thereof. In an example, the vehicle consists of the co-solvent, the anti-kogation agent, the anti-decel agent, the surfactant, the biocide, a pH adjuster, or a combination thereof. In another example, the vehicle consists of water and the co-solvent, the anti-kogation agent, the anti-decel agent, the surfactant, the biocide, a pH adjuster, or a combination thereof. In still another example, the vehicle consists of the anti-kogation agent, the anti-decel agent, the surfactant, the biocide, a pH adjuster, and water. In yet a further example, the vehicle consists of water and the co-solvent, the anti-kogation agent, the surfactant, the chelating agent, the biocide, a pH adjuster, or a combination thereof.

The vehicle may include co-solvent(s). The co-solvent(s) may be present in an amount ranging from about 4 wt % to about 30 wt % (based on the total weight of the inkjet ink). In an example, the vehicle includes glycerol. Other examples of co-solvents include alcohols, aliphatic alcohols, aromatic alcohols, diols, glycol ethers, polyglycol ethers, caprolactams, formamides, acetamides, and long chain alcohols. Examples of such compounds include primary aliphatic alcohols, secondary aliphatic alcohols, 1,2-alcohols, 1,3-alcohols, 1,5-alcohols, ethylene glycol alkyl ethers, propylene glycol alkyl ethers, higher homologs (C₆-C₁₂) of polyethylene glycol alkyl ethers, N-alkyl caprolactams, unsubstituted caprolactams, both substituted and unsubstituted formam ides, both substituted and unsubstituted acetamides, and the like. Specific examples of alcohols may include ethanol, isopropyl alcohol, butyl alcohol, and benzyl alcohol. Other specific examples include 2-ethyl-2-(hydroxymethyl)-1,3-propane diol (EPHD), 2-methyl-1,3-propanediol, 1,2-butanediol, dimethyl sulfoxide, sulfolane, and/or alkyldiols such as 1,2-hexanediol.

The co-solvent may also be a polyhydric alcohol or a polyhydric alcohol derivative. Examples of polyhydric alcohols may include ethylene glycol, diethylene glycol, propylene glycol, butylene glycol, triethylene glycol, 1,5-pentanediol, 1,2-hexanediol, 1,2,6-hexanetriol, glycerin, trimethylolpropane, and xylitol. Examples of polyhydric alcohol derivatives may include an ethylene oxide adduct of diglycerin.

The co-solvent may also be a nitrogen-containing solvent. Examples of nitrogen-containing solvents may include 2-pyrrolidone, 1-(2-hydroxyethyl)-2-pyrrolidone, N-methyl-2-pyrrolidone, cyclohexylpyrrolidone, and triethanolamine.

An anti-kogation agent may also be included in the vehicle of a thermal inkjet formulation. Kogation refers to the deposit of dried ink on a heating element of a thermal inkjet printhead. Anti-kogation agent(s) is/are included to assist in preventing the buildup of kogation. In some examples, the anti-kogation agent may improve the jettability of the thermal inkjet ink. The anti-kogation agent may be present in the thermal inkjet ink in an amount ranging from about 0.1 wt % active to about 1.5 wt % active, based on the total weight of the thermal inkjet ink. In an example, the anti-kogation agent is present in the thermally curable inkjet ink in an amount of about 0.5 wt % active, based on the total weight of the thermally curable inkjet ink.

Examples of suitable anti-kogation agents include oleth-3-phosphate (commercially available as CRODAFOS™ O3 A or CRODAFOS™ N-3A) or dextran 500k. Other suitable examples of the anti-kogation agents include CRODAFOS™ HCE (phosphate-ester from Croda Int.), CRODAFOS® N10 (oleth-10-phosphate from Croda Int.), or DISPERSOGEN® LFH (polymeric dispersing agent with aromatic anchoring groups, acid form, anionic, from Clariant), etc.

The vehicle may include anti-decel agent(s). Decel refers to a decrease in drop velocity over time with continuous firing. Anti-decel agent(s) is/are included to assist in preventing decel. In some examples, the anti-decel agent may improve the jettability of the inkjet ink. The anti-decel agent may be present in an amount ranging from about 0.2 wt % active to about 5 wt % active (based on the total weight of the inkjet ink). In an example, the anti-decel agent is present in the thermally curable inkjet ink in an amount of about 1 wt % active, based on the total weight of the thermally curable inkjet ink.

An example of a suitable anti-decel agent is ethoxylated glycerin having the following formula:

in which the total of a+b+c ranges from about 5 to about 60, or in other examples, from about 20 to about 30. An example of the ethoxylated glycerin is LIPON IC® EG-1 (LEG-1, glycereth-26, a+b+c=26, available from Lipo Chemicals).

The vehicle of the thermally curable inkjet ink may also include surfactant(s). In any of the examples disclosed herein, the surfactant may be present in an amount ranging from about 0.01 wt % active to about 5 wt % active (based on the total weight of the inkjet ink). In an example, the surfactant is present in the inkjet ink in an amount ranging from about 0.05 wt % active to about 3 wt % active, based on the total weight of the thermally curable inkjet ink.

The surfactant may include anionic and/or non-ionic surfactants. Examples of the anionic surfactant may include alkylbenzene sulfonate, alkylphenyl sulfonate, alkylnaphthalene sulfonate, higher fatty acid salt, sulfate ester salt of higher fatty acid ester, sulfonate of higher fatty acid ester, sulfate ester salt and sulfonate of higher alcohol ether, higher alkyl sulfosuccinate, polyoxyethylene alkylether carboxylate, polyoxyethylene alkylether sulfate, alkyl phosphate, and polyoxyethylene alkyl ether phosphate. Specific examples of the anionic surfactant may include dodecylbenzenesulfonate, isopropylnaphthalenesulfonate, monobutylphenylphenol monosulfonate, monobutylbiphenyl sulfonate, monobutylbiphenylsul fonate, and dibutylphenylphenol disulfonate. Examples of the non-ionic surfactant may include polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene fatty acid ester, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene sorbitol fatty acid ester, glycerin fatty acid ester, polyoxyethylene glycerin fatty acid ester, polyglycerin fatty acid ester, polyoxyethylene alkylamine, polyoxyethylene fatty acid amide, alkylalkanolamide, polyethylene glycol polypropylene glycol block copolymer, acetylene glycol, and a polyoxyethylene adduct of acetylene glycol. Specific examples of the non-ionic surfactant may include polyoxyethylenenonyl phenylether, polyoxyethyleneoctyl phenylether, and polyoxyethylenedodecyl. Further examples of the non-ionic surfactant may include silicon surfactants such as a polysiloxane oxyethylene adduct; fluorine surfactants such as perfluoroalkylcarboxylate, perfluoroalkyl sulfonate, and oxyethyleneperfluoro alkylether; and biosurfactants such as spiculisporic acid, rhamnolipid, and lysolecithin.

In some examples, the vehicle may include a silicone-free alkoxylated alcohol surfactant such as, for example, TEGO® Wet 510 (EvonikTegoChemie GmbH) and/or a self-emulsifiable wetting agent based on acetylenic diol chemistry, such as, for example, SURFYNOL® SE-F (Air Products and Chemicals, Inc.). Other suitable commercially available surfactants include SURFYNOL® 465 (ethoxylatedacetylenic diol), SURFYNOL® 440 (an ethoxylated low-foam wetting agent) SURFYNOL® CT-211 (now CARBOWET® GA-211, non-ionic, alkylphenylethoxylate and solvent free), and SURFYNOL® 104 (non-ionic wetting agent based on acetylenic diol chemistry), (all of which are from Air Products and Chemicals, Inc.); ZONYL® FSO (a.k.a. CAPSTONE®, which is a water-soluble, ethoxylated non-ionic fluorosurfactant from Dupont); TERGITOL® TMN-3 and TERGITOL® TMN-6 (both of which are branched secondary alcohol ethoxylate, non-ionic surfactants), and TERGITOL® 15-S-3, TERGITOL® 15-S-5, and TERGITOL® 15-S-7 (each of which is a secondary alcohol ethoxylate, non-ionic surfactant) (all of the TERGITOL® surfactants are available from The Dow Chemical Co.).

The chelating agent is another example of an additive that may be included in the aqueous ink vehicle. When included, the chelating agent is present in an amount greater than 0 wt % active and less than or equal to 0.5 wt % active based on the total weight of the thermally curable inkjet ink. In an example, the chelating agent is present in an amount ranging from about 0.05 wt % active to about 0.2 wt % active based on the total weight of the thermally curable inkjet ink.

In an example, the chelating agent is selected from the group consisting of methylglycinediacetic acid, trisodium salt; 4,5-dihydroxy-1,3-benzenedisulfonic acid disodium salt monohydrate; ethylenediaminetetraacetic acid (EDTA); hexamethylenediamine tetra(methylene phosphonic acid), potassium salt; and combinations thereof. Methylglycinediacetic acid, trisodium salt (Na3MGDA) is commercially available as TRILON® M from BASF Corp. 4,5-dihydroxy-1,3-benzenedisulfonic acid disodium salt monohydrate is commercially available as TIRON™ monohydrate. Hexamethylenediamine tetra(methylene phosphonic acid), potassium salt is commercially available as DEQUEST® 2054 from Italmatch Chemicals.

The vehicle may also include biocide(s) (i.e., antimicrobial agents). In an example, the total amount of biocide(s) in the thermally curable inkjet ink ranges from about 0.1 wt % active to about 0.25 wt % active (based on the total weight of the inkjet ink). In another example, the total amount of biocide(s) in the inkjet ink is about 0.22 wt % active (based on the total weight of the inkjet ink). In some instances, the biocide may be present in the pigment dispersion that is mixed with the vehicle.

Examples of suitable biocides include the NUOSEPT® (Ashland Inc.), UCARCIDE™ or KORDEK™ or ROCIMA™ (Dow Chemical Co.), PROXEL® (Arch Chemicals) series, ACTICIDE® B20 and ACTICIDE® M20 and ACTICIDE® MBL (blends of 2-methyl-4-isothiazolin-3-one (MIT), 1,2-benzisothiazolin-3-one (BIT) and Bronopol) (Thor Chemicals), AXIDE™ (Planet Chemical), NIPACIDE™ (Clariant), blends of 5-chloro-2-methyl-4-isothiazolin-3-one (CIT or CMIT) and MIT under the tradename KATHON™ (Dow Chemical Co.), and combinations thereof.

The vehicle may also include a pH adjuster. A pH adjuster may be included in the thermally curable inkjet ink to achieve a desired pH (e.g., a pH of about 8.5) and/or to counteract any slight pH drop that may occur over time. In an example, the total amount of pH adjuster(s) in the thermally curable inkjet ink ranges from greater than 0 wt % to about 0.1 wt % (based on the total weight of the thermal inkjet ink). In another example, the total amount of pH adjuster(s) in the thermally curable inkjet ink is about 0.03 wt % (based on the total weight of the thermally curable inkjet ink).

Examples of suitable pH adjusters include metal hydroxide bases, such as potassium hydroxide (KOH), sodium hydroxide (NaOH), etc. In an example, the metal hydroxide base may be added to the thermal inkjet ink in an aqueous solution. In another example, the metal hydroxide base may be added to the thermal inkjet ink in an aqueous solution including 5 wt % of the metal hydroxide base (e.g., a 5 wt % potassium hydroxide aqueous solution).

Suitable pH ranges for examples of the ink can be from pH 7 to pH 11, from pH 7 to pH 10, from pH 7.2 to pH 10, from pH 7.5 to pH 10, from pH 8 to pH 10, 7 to pH 9, from pH 7.2 to pH 9, from pH 7.5 to pH 9, from pH 8 to pH 9, from 7 to pH 8.5, from pH 7.2 to pH 8.5, from pH 7.5 to pH 8.5, from pH 8 to pH 8.5, from 7 to pH 8, from pH 7.2 to pH 8, or from pH 7.5 to pH 8.

The balance of the thermally curable inkjet ink is water. In an example, deionized water may be used. The water included in the thermally curable inkjet ink may be: i) part of the pigment dispersion and/or binder dispersion, ii) part of the vehicle, iii) added to a mixture of the pigment dispersion and/or binder dispersion and the vehicle, or iv) a combination thereof. In examples where the thermally curable inkjet ink is a thermal inkjet ink, the liquid vehicle is an aqueous based vehicle including at least 70% by weight of water. In examples where the thermally curable inkjet ink is a piezoelectric inkjet ink, the liquid vehicle is a solvent based vehicle including at least 50% by weight of the co-solvent.

Pre-treatment Composition

In some of the examples disclosed herein, a pre-treatment composition may be printed with the thermally curable inkjet ink. In an example, the pre-treatment composition a fixing agent selected from the group consisting of a multivalent metal cation, a cationic polymer, and a combination of a multivalent metal cation and a cationic polymer, and an aqueous pre-treatment vehicle.

Some examples of the pre-treatment composition include the multivalent metal salt without the cationic polymer. The multivalent metal salt includes a multivalent metal cation and an anion. In an example, the multivalent metal salt includes a multivalent metal cation selected from the group consisting of a calcium cation, a magnesium cation, a zinc cation, an iron cation, an aluminum cation, and combinations thereof; and an anion selected from the group consisting of a chloride anion, an iodide anion, a bromide anion, a nitrate anion, a carboxylate anion, a sulfonate anion, a sulfate anion, and combinations thereof.

It is to be understood that the multivalent metal salt (containing the multivalent metal cation) may be present in any suitable amount. In an example, the metal salt is present in an amount ranging from about 2 wt % to about 15 wt % based on a total weight of the pre-treatment composition. In further examples, the metal salt is present in an amount ranging from about 4 wt % to about 12 wt %; or from about 5 wt % to about 15 wt %; or from about 6 wt % to about 10 wt %, based on a total weight of the pre-treatment composition.

Some examples of the pre-treatment composition include the cationic polymer without the multivalent metal salt. When the pre-treatment composition is to be thermal inkjet printed, the cationic polymer included in the pre-treatment composition has a weight average molecular weight (g/mol) of 100,000 or less. This molecular weight enables the cationic polymer to be printed by thermal inkjet printheads. In some examples, the weight average molecular weight of the cationic polymer ranges from about 800 to about 40,000. It is expected that a cationic polymer with a weight average molecular weight higher than 100,000 can be used for examples of the pre-treatment composition applied by piezoelectric printheads and analog methods. As such, in other examples, the cationic polymer may have a weight average molecular weight higher than 100,000, such as, for example, up to 600,000.

Examples of the cationic polymer are selected from the group consisting of poly(diallyldimethylammonium chloride); poly(methylene-co-guanidine) anion, wherein the anion is selected from the group consisting of hydrochloride, bromide, nitrate, sulfate, and sulfonates; a polyamine; and poly(dimethylamine-co-epichlorohydrin).

In an example, the cationic polymer is present in an amount ranging from about 1 wt % active to about 10 wt % active based on a total weight of the pre-treatment composition. In further examples, the cationic polymer is present in an amount ranging from about 4 wt % active to about 8 wt % active; or from about 2 wt % active to about 7 wt % active; or from about 6 wt % active to about 10 wt % active, based on a total weight of the pre-treatment composition.

In still other examples, the multivalent metal cation is used in combination with the cationic polymer.

As used herein, the term “aqueous pre-treatment vehicle” may refer to the liquid fluid in which the multivalent metal salt, or the cationic polymer, or the multivalent metal salt in combination with the cationic polymer, is/are mixed to form the pre-treatment composition.

In an example of the pre-treatment composition, the aqueous vehicle includes water and a co-solvent. Examples of suitable co-solvents for the pre-treatment composition are water soluble or water miscible co-solvents that may be selected from the group consisting of glycerol, ethoxylated glycerol, 2-methyl-1,3-propanediol, trimethylolpropane, 1,2-propanediol, dipropylene glycol, and combinations thereof. Other suitable examples of co-solvents include polyhydric alcohols or simple carbohydrates (e.g., trehalose). Still further examples of the pre-treatment composition co-solvent(s) may include alcohols (e.g., diols), ketones, ketoalcohols, ethers (e.g., the cyclic ether tetrahydrofuran (THF), and others, such as thiodiglycol, sulfolane, 2-pyrrolidone, 1-(2-hydroxyethyl)-2-pyrrolidone,1,3-dimethyl-2-imidazolidinone and caprolactam; glycols such as ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, trimethylene glycol, butylene glycol, and hexylene glycol; addition polymers of oxyethylene or oxypropylene such as polyethylene glycol, polypropylene glycol and the like; triols such as glycerol (as mentioned above) and 1,2,6-hexanetriol; lower alkyl ethers of polyhydric alcohols, such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monomethyl, and diethylene glycol monoethyl ether; and lower dialkyl ethers of polyhydric alcohols, such as diethylene glycol dimethyl or diethyl ether.

Whether used alone or in combination, the total amount of the co-solvent(s) may be present in the pre-treatment composition in an amount ranging from about 5 wt % to about 25 wt % based on a total weight of the pre-treatment composition. The amounts in this range may be particularly suitable for the composition when it is to be dispensed from a thermal inkjet printhead. In another example, the total amount of the co-solvent(s) may be present in the pre-treatment composition in an amount ranging from about 10 wt % to about 18 wt % based on a total weight of the pre-treatment composition. The co-solvent amount may be increased to increase the viscosity of the pre-treatment composition for a high viscosity piezoelectric printhead.

It is to be understood that water is present in addition to the co-solvent(s) and makes up a balance of the pre-treatment composition. As such, the weight percentage of the water present in the pre-treatment composition will depend, in part, upon the weight percentages of the other components. The water may be purified water or deionized water.

An example of the pre-treatment composition further comprises an additive selected from the group consisting of a surfactant, a chelating agent, a buffer, a biocide, and combinations thereof.

Some examples of the pre-treatment composition further include a surfactant. The surfactant may be any surfactant that aids in wetting, but that does not deleteriously interact with the salt in the pre-treatment composition. As such, in an example, the surfactant in the pre-treatment composition is selected from the group consisting of a non-ionic surfactant and a zwitterionic surfactant. The amount of the surfactant that may be present in the pre-treatment composition is 2 wt % active or less (with the lower limit being above 0) based on the total weight of the pre-treatment composition. In some examples, the amount of the surfactant ranges from about 0.05 wt % active to about 1 wt % active based on the total weight of the pre-treatment composition.

Examples of suitable non-ionic surfactants include non-ionic fluorosurfactants, non-ionic acetylenic diol surfactants, non-ionic ethoxylated alcohol surfactants, non-ionic silicone surfactants, and combinations thereof. Several commercially available non-ionic surfactants that can be used in the formulation of the pre-treatment composition include ethoxylated alcohols/secondary alcohol ethoxylates such as those from the TERGITOL® series (e.g., TERGITOL® 15-S-30, TERGITOL® 15-S-9, TERGITOL® 15-S-7), manufactured by Dow Chemical; surfactants from the SURFYNOL® series (e.g., SURFYNOL® SE-F (i.e., a self-emulsifiable wetting agent based on acetylenic diol chemistry), SURFYNOL® 440 and SURFYNOL® 465 (i.e., ethoxylated 2,4,7,9-tetramethyl 5 decyn-4,7-diol)) manufactured by Evonik Industries, and the DYNOL™ series (e.g., DYNOL™ 607 and DYNOL™ 604) manufactured by Air Products and Chemicals, Inc.; fluorinated surfactants, such as those from the ZONYL® family (e.g., ZONYL® FSO and ZONYL® FSN surfactants), manufactured by E.I. DuPont de Nemours and Company; alkoxylated surfactants such as TEGO® Wet 510 manufactured from Evonik; fluorinated POLYFOX® non-ionic surfactants (e.g., PF159 non-ionic surfactants), manufactured by Omnova; silicone surfactants, such as those from BYK® 340 series (e.g., BYK® 345, BYK® 346, BYK® 347, BYK® 348, BYK® 349) manufactured by BYK Chemie; or combinations thereof.

Examples of suitable zwitterionic (amphoteric) surfactants that may be used in the pre-treatment composition include coco-betaine, alkyl isothionates, N,N-dimethyl-N-dodecylamine oxide, N,N-dimethyl-N-tetradecyl amine oxide (i.e., myristamine oxide), N,N-dimethyl-N-hexadecyl amine oxide, N,N-dimethyl-N-octadecyl amine oxide, N,N-dimethyl-N—(Z-9-octadecenyl)-N-amine oxide, N-dodecyl-N,N-dimethyl glycine, lecithins, phospatidylethanolamine, phosphatidylcholine, and phosphatidylserine.

The chelating agent is another example of an additive that may be included in the pre-treatment composition. When included, the chelating agent is present in an amount greater than 0 wt % active and less than or equal to 0.5 wt % active based on the total weight of the pre-treatment composition. Any example of the chelating agent described in reference to the thermally curable inkjet ink may be used in the pre-treatment composition.

Buffers are another example of an additive that may be included in the pre-treatment composition. In an example, the total amount of buffer(s) in the pre-treatment composition ranges from 0 wt % to about 0.5 wt % (with respect to the weight of pre-treatment composition). In another example, the total amount of buffer(s) in the ink is about 0.1 wt % (with respect to the weight of pre-treatment composition).

Examples of some suitable buffers include TRIS (tris(hydroxymethyl)aminomethane or Trizma), bis-tris propane, TES (2-[(2-Hydroxy-1,1-bis(hydroxymethyl)ethyl)amino]ethanesulfonic acid), MES (2-ethanesulfonic acid), MOPS (3-(N-morpholino)propanesulfonic acid), HEPES (4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid), DIPSO (3-(N,N-Bis[2-hydroxyethyl]amino)-2-hydroxypropanesulfonic acid), Tricine (N-[tris(hydroxymethyl)methyl]glycine), HEPPSO (β-Hydroxy-4-(2-hydroxyethyl)-1-piperazinepropanesulfonic acid monohydrate), POPSO (Piperazine-1,4-bis(2-hydroxypropanesulfonic acid) dihydrate), EPPS (4-(2-Hydroxyethyl)-1-piperazinepropanesulfonic acid, 4-(2-Hydroxyethyl)piperazine-1-propanesulfonic acid), TEA (triethanolamine buffer solution), Gly-Gly (Diglycine), bicine (N,N-Bis(2-hydroxyethyl)glycine), HEPBS (N-(2-Hydroxyethyl)piperazine-N′-(4-butanesulfonic acid)), TAPS ([tris(hydroxymethyl)methylamino]propanesulfonic acid), AMPD (2-amino-2-methyl-1,3-propanediol), TABS (N-tris(Hydroxymethyl)methyl-4-aminobutanesulfonic acid), or the like.

Biocides (also referred to herein as antimicrobial agents) are another example of an additive that may be included in the pre-treatment composition. In an example, the total amount of biocide(s) in the pre-treatment composition ranges from about 0 wt % active to about 0.1 wt % active (with respect to the weight of the pre-treatment composition). In another example, the total amount of biocide(s) in the pre-treatment composition ranges from about 0.001 wt % active to about 0.1 wt % active (with respect to the weight of the pre-treatment composition). Any example of the biocide described in reference to the thermally curable inkjet ink may be used in the pre-treatment composition.

The pH of the pre-treatment composition can be less than 7. In some examples, the pH ranges from pH 1 to pH 7, from pH 3 to pH 7, from pH 4.5 to pH 7, etc.

In an example, the inkjet pre-treatment composition consists of the listed components and no additional components (such as water soluble polymers, water repellent agents, etc.). In other examples, the inkjet pre-treatment composition comprises the listed components, and other components that do not deleteriously affect the jettability of the fluid via a thermal- or piezoelectric inkjet printhead may be added.

Examples of the pre-treatment composition disclosed herein may be used in a thermal inkjet printer or in a piezoelectric printer to pre-treat a textile substrate. The viscosity of the pre-treatment composition may be adjusted for the type of printhead that is to be used, and the viscosity may be adjusted by adjusting the co-solvent level and/or adding a viscosity modifier. When used in a thermal inkjet printer, the viscosity of the pre-treatment composition may be modified to range from about 1 centipoise (cP) to about 9 cP (at 20° C. to 25° C.), and when used in a piezoelectric printer, the viscosity of the pre-treatment composition may be modified to range from about 2 cP to about 20 cP (at 20° C. to 25° C.), depending on the viscosity of the printhead that is being used (e.g., low viscosity printheads, medium viscosity printheads, or high viscosity printheads).

One specific example of the pre-treatment composition includes the multivalent metal salt in an amount ranging from about 5 wt % to about 15 wt % based on the total weight of the pre-treatment composition; an additive selected from the group consisting of a non-ionic surfactant, a chelating agent, an antimicrobial agent, and combinations thereof; and the aqueous vehicle, which includes water and an organic solvent (e.g., the co-solvent).

Textile Fabrics

In the examples disclosed herein, the textile fabric is selected from the group consisting of cotton fabrics, cotton blend fabrics, nylon fabrics, nylon blend fabrics, polyester fabrics, polyester blend fabrics, silk fabrics, silk blend fabrics, spandex, spandex blend fabrics, rayon, and rayon blend fabrics. In a further example, textile fabric is selected from the group consisting of cotton fabrics and cotton blend fabrics. Blends may include the listed material in combination with one or more other material(s). An example of a tri-blend includes cotton, polyester and spandex.

It is to be understood that organic textile fabrics and/or inorganic textile fabrics may be used for the textile fabric. Some types of fabrics that can be used include various fabrics of natural and/or synthetic fibers.

Example natural fiber fabrics that can be used include treated or untreated natural fabric textile substrates, e.g., wool, cotton, silk, linen, jute, flax, hemp, rayon fibers, thermoplastic aliphatic polymeric fibers derived from renewable resources (e.g. cornstarch, tapioca products, sugarcanes), etc. Example synthetic fibers used in the textile fabric/substrate can include polymeric fibers such as nylon fibers, polyvinyl chloride (PVC) fibers, PVC-free fibers made of polyester, polyamide, polyimide, polyacrylic, polypropylene, polyethylene, polyurethane, polystyrene, polyaramid (e.g., Kevlar®) polytetrafluoroethylene (Teflon®) (both trademarks of E.I. du Pont de Nemours and Company, Delaware), fiberglass, polytrimethylene, polycarbonate, polyethylene terephthalate, polyester terephthalate, polybutylene terephthalate, or a combination thereof. In some examples, the fiber can be a modified fiber from the above-listed polymers. The term “modified fiber” refers to one or both of the polymeric fiber and the fabric as a whole having undergone a chemical or physical process such as, but not limited to, copolymerization with monomers of other polymers, a chemical grafting reaction to contact a chemical functional group with one or both the polymeric fiber and a surface of the fabric, a plasma treatment, a solvent treatment, acid etching, or a biological treatment, an enzyme treatment, or antimicrobial treatment to prevent biological degradation.

It is to be understood that the terms “textile fabric” or “fabric substrate” do not include materials commonly known as any kind of paper (even though paper can include multiple types of natural and synthetic fibers or mixtures of both types of fibers). Fabric substrates can include textiles in filament form, textiles in the form of fabric material, or textiles in the form of fabric that has been crafted into finished articles (e.g., clothing, blankets, tablecloths, napkins, towels, bedding material, curtains, carpet, handbags, shoes, banners, signs, flags, etc.). In some examples, the fabric substrate can have a woven, knitted, non-woven, or tufted fabric structure. In one example, the fabric substrate can be a woven fabric where warp yarns and weft yarns can be mutually positioned at an angle of about 90°. This woven fabric can include fabric with a plain weave structure, fabric with twill weave structure where the twill weave produces diagonal lines on a face of the fabric, or a satin weave. In another example, the fabric substrate can be a knitted fabric with a loop structure. The loop structure can be a warp-knit fabric, a weft-knit fabric, or a combination thereof. A warp-knit fabric refers to every loop in a fabric structure that can be formed from a separate yarn mainly introduced in a longitudinal fabric direction. A weft-knit fabric refers to loops of one row of fabric that can be formed from the same yarn. In a further example, the fabric substrate can be a non-woven fabric. For example, the non-woven fabric can be a flexible fabric that can include a plurality of fibers or filaments that are one or both bonded together and interlocked together by a chemical treatment process (e.g., a solvent treatment), a mechanical treatment process (e.g., embossing), a thermal treatment process, or a combination of multiple processes.

Printing Methods and System

FIG. 1 depicts an example of the printing method 100. As shown in FIG. 1, an example the printing method 100 comprises: applying a thermally curable ink composition on a fabric substrate, the thermally curable ink composition including: from about 1 wt % active to about 6 wt % active of a pigment that absorbs ultraviolet radiation, infrared radiation, or a combination thereof, based on a total weight of the thermally curable ink composition; from about 2 wt % active to about 20 wt % active of a polymeric binder, based on a total weight of the thermally curable ink composition; and an aqueous ink vehicle (reference numeral 102); and selectively heating the pigment of the thermally curable ink composition applied on the fabric substrate by exposing the fabric substrate to an emission wavelength from a narrow wavelength light source for a total exposure time of 3 seconds or less, thereby thermally fixing the pigment to the fabric substrate (reference numeral 104).

As used herein, the phrase “total exposure time” refers to the total time that the fabric having the ink printed thereon is exposed to the emission wavelength. In some examples, the total exposure time may take place during a single event where the light source is turned on (i.e., light source on event). In other examples, the total exposure time may take place over a series of light source on events that are shorter in duration than the total exposure time and whose sum equals the total exposure time. In some examples, light source on events may be separated by light source off events, during which the light source is turned off and the fabric is not exposed to the emission wavelength. In these examples, the total time to achieve pigment fixation is longer than the total exposure time due to the time periods when the light source is off. However, in these examples, the total exposure time is still 3 seconds or less because the fabric is not exposure to the light emission during the off events.

It is to be understood that any example of the thermally curable ink composition may be used in the examples of the method 100. It is to be understood that any example of the textile fabric may also be used in the examples of the method 100. The thermally curable ink composition may be ejected onto the textile fabric using any suitable applicator, such as a thermal inkjet printhead, a piezoelectric printhead, a continuous inkjet printhead, etc. The applicator may eject the thermally curable ink composition in a single pass or in multiple passes. As an example of single pass printing, the cartridge(s) of an inkjet printer deposit the desired amount of the ink composition during the same pass of the cartridge(s) across the textile fabric. In other examples, the cartridge(s) of an inkjet printer deposit the desired amount of the ink composition over several passes of the cartridge(s) across the textile fabric. In other examples of the method 100, the thermally curable ink composition is applied via analog methods, such as screen printing, spraying, roll-coating, cylindrical pad printing, etc.

In one example of the method 100, the narrow wavelength light source is a light emitting diode having an emission wavelength ranging from about 10 nm to about 400 nm. In one example, the narrow wavelength ultraviolet light source is a light emitting diode having an emission wavelength ranging from about 365 nm to about 395 nm. In another example, the narrow wavelength ultraviolet light source is a 395 nm light emitting diode. In another example of the method 100, the narrow wavelength light source is a light emitting diode having an emission wavelength ranging from about 760 nm to about 1 mm.

The UV or IR radiation exposure takes place very rapidly with the narrow wavelength light source. To avoid overheating of the pigment, it may be desirable to adjust the settings of the narrow wavelength light source. For example, the method 100 may include setting the narrow wavelength light source to a power setting ranging from about 3.5 W/cm² to about 10 W/cm². The power setting may depend, in part, upon the light source used, the total time for exposure, the distance between the light source and the textile fabric, etc. Higher power settings may be desirable for faster throughput systems. In another example, the energy (radiant) exposure ranges from about 2 J/cm² to about 28 J/cm². In a specific example, if a power of 10 W/cm² is applied for 1 second, the applied energy is 10 J/cm².

When exposed to the UV or IR radiation, the pigment in the printed ink absorbs the ultraviolet light or infrared light and heats up to its fixation temperature. As such, exposure to the narrow wavelength light source fixes the ink on the textile fabric. It has been found that the narrow wavelength light source thermally cures the thermally curable ink composition disclosed herein within 3 seconds or less, and effectively fixes the pigment to the textile fabric without traditional UV curing components, such as photoinitiators.

In some examples of the method 100, the desired amount of the thermally curable ink composition is deposited in a single pass or in multiple passes, and then selective heating occurs. In these examples, the application of the thermally curable ink composition occurs prior to the selectively heating, and the selectively heating involves intermittent light source on events and light source off events. During light source on events, the narrow wavelength light source is turned on, and during light source off events, the narrow wavelength light source is turned off. The intermittent on and off events can effectively heat the pigment in the printed ink to its fixation temperature without overheating the pigment. The light source on events may range from about 0.1 second to about 1.5 seconds. Since the total exposure time is 3 seconds or less, the number of light source on events will depend upon the duration of each on event and the desired total exposure time. For example, when each light source on event is 1 second long, a total of three light source on events may take place so that the total exposure time is 3 seconds. A higher number of light source on events may be used when the on events are shorter in duration. The light source off events may be long enough to allow the pigments to cool without allowing the pigments to return to their pre-exposure temperature.

In some other examples of the method 100, the desired amount of the thermally curable ink composition is deposited in multiple passes, and selective heating occurs after each pass. In these examples, the applying of the thermally curable ink composition is accomplished in multiple print passes, and the method 100 further includes exposing the fabric substrate to the narrow wavelength light source after each print pass for a time less than the total exposure time. The time for exposing the fabric substrate to the narrow wavelength light source after each print pass ranges from about 0.1 second to about 1.5 seconds. Since the total exposure time is 3 seconds or less, the duration of the exposure after each pass will depend upon the number of passes and the desired total exposure time. For example, when the ink is to be deposited in two printing passes and the total exposure time is 2 seconds, each of the exposures may take place for 1 second.

In some examples of the method 100, warming and/or cooling of the textile fabric may take place before and/or concurrently with UV and/or IR radiation exposure. As such, some examples of the method 100 include warming or cooling the fabric substrate having the thermally curable ink composition thereon at a temperature below a fixation temperature of the thermally curable ink composition: i) before the selectively heating; or ii) concurrently with the selectively heating; or iii) both before and concurrently with the selectively heating.

Warming may be accomplished with a heat source that is positioned above the textile fabric (e.g., an infrared heating lamp that provides radiative heating/warming) or below the fabric substrate (a conductive platen that provides conductive heating/warming). In an example of the printing method 100, the temperature at which the fabric substrate is warmed ranges from about 60° C. to about 100° C. In another example, the temperature at which the textile fabric is warmed ranges from about 70° C. to about 90° C. It is to be understood that this warming temperature range may vary, depending upon, e.g., the fixation temperature of the thermally curable ink. For example, if the fixation temperature of an ink were 160° C., the warming temperature may be any suitable temperature below 160° C.

Cooling may be accomplished with a cold air source that is positioned above the textile fabric or below the fabric substrate. In an example of the printing method 100, the temperature at which the fabric substrate is cooled ranges from about 20° C. to about 60° C. It is to be understood that this cooling temperature range may vary, depending upon, e.g., the fixation temperature of the thermally curable ink. For example, if the fixation temperature of an ink were 160° C., the cooling temperature may be any suitable temperature that enables the fabric substrate to reach 160° C. without overheating.

In other instances, warming or cooling may be accomplished with any suitable bulk temperature control mechanism.

In an example of the printing method 100, the warming or cooling takes place for an amount of time ranging from about 0.1 seconds to about 30 seconds. In another example, the warming or cooling takes place for an amount of time ranging from about 0.1 seconds to about 3 seconds. It is to be understood that this warming or cooling time range may vary, depending upon, e.g., the temperature at which warming or cooling takes place and whether warming or cooling is accomplished prior to and/or concurrently with the UV and/or IR radiation exposure. For example, if warming or cooling occurs concurrently with UV and/or IR radiation exposure, the time for warming or cooling may range from about 0.1 second up to 3 seconds. For another example, if warming occurs prior to UV and/or IR radiation exposure, the time for warming may be longer, e.g., up to 30 seconds. It is to be further understood that examples of the method 100 may be accomplished without warming/pre-heating or without cooling.

FIG. 2 depicts another example of the printing method 200. As shown in FIG. 2, this example the printing method 200 comprises: applying a pre-treatment composition on a fabric substrate, the pre-treatment composition including: a fixing agent selected from the group consisting of a multivalent metal cation, a cationic polymer, and a combination of the multivalent metal cation and the cationic polymer; and an aqueous pre-treatment vehicle (reference numeral 202); applying a thermally curable ink composition on the fabric substrate, the thermally curable ink composition including: from about 1 wt % active to about 6 wt % active of a pigment that absorbs ultraviolet radiation, infrared radiation, or a combination thereof, based on a total weight of the thermally curable ink composition; from about 2 wt % active to about 20 wt % active of a polymeric binder, based on a total weight of the thermally curable ink composition; and an aqueous ink vehicle (reference numeral 204; and selectively heating the pigment of the thermally curable ink composition applied on the fabric substrate by exposing the fabric substrate to an emission wavelength from a narrow wavelength light source for a total exposure time of 3 seconds or less, thereby thermally fixing the pigment to the fabric substrate (reference numeral 206).

It is to be understood that any example of the pre-treatment composition may be used in the examples of the method 200. In some examples, the pre-treatment composition may be applied digitally using inkjet technology. Besides inkjet methods, the pretreatment composition can also be applied to fabric substrates via analog methods, e.g., spraying, roll-coating, cylindrical pad printing, etc. With these analog methods, the pre-treatment composition is applied to the entire fabric substrate.

It is also to be understood that any example of the thermally curable ink composition may be used in the examples of the method 200. The thermally curable ink composition may be ejected onto the textile fabric using any suitable applicator, such as a thermal inkjet printhead, a piezoelectric printhead, a continuous inkjet printhead, etc. The applicator may eject the thermally curable ink composition in a single pass or in multiple passes as described in reference to the method 100. In other examples of the method 200, the thermally curable ink composition is applied via analog methods, such as screen printing, spraying, roll-coating, cylindrical pad printing, etc.

In one example of the method 200, the narrow wavelength light source is a light emitting diode having an emission wavelength ranging from about 10 nm to about 400 nm. In one example, the narrow wavelength ultraviolet light source is a light emitting diode having an emission wavelength ranging from about 365 nm to about 395 nm. In another example, the narrow wavelength ultraviolet light source is a 395 nm light emitting diode. In another example of the method 200, the narrow wavelength light source is a light emitting diode having an emission wavelength ranging from about 760 nm to about 1 mm.

The method 200 may also include setting the narrow wavelength light source so that the energy exposure ranges from about 2 J/cm² to about 28 J/cm².

When exposed to the UV or IR radiation, the pigment in the printed ink absorbs the ultraviolet or infrared light and heats up to its fixation temperature. As such, exposure to the narrow wavelength light source fixes the ink on the textile fabric. In the method 200, the multivalent metal salt in the pre-treatment composition also interacts with pigment in the ink directly on the fabric substrate, which helps fix the pigment and improve the optical density.

In some examples of the method 200, the desired amount of the pre-treatment composition and of thermally curable ink composition is deposited in a single pass or in multiple passes, and then selective heating occurs. In these examples, the application of the pre-treatment composition occurs prior to the application of the thermally curable ink composition, the application of the thermally curable ink composition occurs prior to the selectively heating, and the selectively heating involves intermittent light source on events and light source off events. During light source on events, the narrow wavelength light source is turned on, and during light source off events, the narrow wavelength light source is turned off. The intermittent on and off events can effectively heat the pigment in the printed ink to its fixation temperature without overheating the pigment. The light source on events may range from about 0.1 second to about 1.5 seconds. Since the total exposure time is 3 seconds or less, the number of light source on events will depend upon the duration of each on event and the desired total exposure time. For example, when each light source on event is 1 second long, a total of three light source on events may take place so that the total exposure time is 3 seconds. A higher number of light source on events may be used when the on events are shorter in duration. The light source off events may be long enough to allow the pigments to cool without allowing the pigments to return to their pre-exposure temperature.

In some other examples of the method 200, the desired amount of the thermally curable ink composition is deposited, the desired amount of the thermally curable ink composition is deposited in multiple passes, and selective heating occurs after each pass. In these examples, the application of the pre-treatment composition occurs prior to the application of the thermally curable ink composition, the applying of the thermally curable ink composition is accomplished in multiple print passes, and the method 200 further includes exposing the fabric substrate to the narrow wavelength light source after each print pass for a time less than the total exposure time. The time for exposing the fabric substrate to the narrow wavelength light source after each print pass ranges from about 0.1 second to about 1 second. Since the total exposure time is 3 seconds or less, the duration of the exposure after each pass will depend upon the number of passes and the desired total exposure time.

In some of these examples, the thermally curable ink composition is printed onto the printed pre-treatment composition while the pre-treatment composition is wet. Wet on wet printing may be desirable because less pre-treatment composition may be applied during this process (as compared to when the pre-treatment composition is dried prior to ink application), and because the printing workflow may be simplified without the additional drying. In an example of wet on wet printing, the thermally curable ink composition is printed onto the printed pre-treatment composition within a period of time ranging from about 0.01 second to about 30 seconds after the printed pre-treatment composition is printed. In further examples, the thermally curable ink composition is printed onto the previously applied pre-treatment composition within a period of time ranging from about 0.1 second to about 20 seconds; or from about 0.2 second to about 10 seconds; or from about 0.2 second to about 5 seconds after the previously applied composition is printed. Wet on wet printing may be accomplished in a single pass.

In other of these examples, drying takes place after the application of the pre-treatment composition and before the application of the thermally curable ink composition. It is to be understood that in this example, drying of the pre-treatment composition may be accomplished in any suitable manner, e.g., air dried (e.g., at a temperature ranging from about 20° C. to about 80° C. for 30 seconds to 5 minutes), or by exposure to heat via any suitable heat source (e.g. for 3 seconds or less), and/or the like.

In some examples of the method 200, warming or cooling of the textile fabric may take place before and/or concurrently with UV and/or IR radiation exposure. As such, some examples of the method 200 include warming or cooling the fabric substrate having the thermally curable ink composition thereon at a temperature below a fixation temperature of the thermally curable ink composition: i) before the selectively heating; or ii) concurrently with the selectively heating; or iii) both before and concurrently with the selectively heating.

Warming or cooling may be performed as described in reference to the method 100.

Referring now to FIGS. 3A and 3B, schematic diagrams of two different printing systems 10, 10′ including inkjet printheads 12, or 12 and 14, or 12′, or 12′ and 14′ and a narrow wavelength light source 18 or 18′.

The example system 10 shown in FIG. 3A illustrates a system for single pass printing and selective heating, and the example system 10′ shown in FIG. 3B illustrates a system for multiple pass printing and single or multiple pass selective heating.

In the example system 10 shown in FIG. 3A, the textile fabric/fabric substrate 20 may be transported through the printing system 10 along the path shown by the arrow 22. In this example, a pagewide printhead 12 (i.e., a series of printheads extending the width of the fabric substrate 20) is in a fixed position relative to the fabric substrate 20. When the fabric substrate 20 is moved relative to the pagewide printhead 12, a single color or multiple colors of the thermally curable ink composition 24 is/are inkjet printed directly onto fabric substrate 20 by the pagewide printhead 12 to form an ink layer. The color(s), amount(s), and arrangement of the thermally curable ink composition(s) 24 that is/are applied depend upon the digital image from which the print is being generated. In this example, after the thermally curable ink composition(s) 24 is/are dispensed, the narrow wavelength light source 18 is operated to expose the fabric substrate 20 having the thermally curable ink composition(s) 24 printed thereon to UV and/or IR radiation 26 for a total exposure time of 3 seconds or less. UV and/or IR radiation exposure may take place in one light source on event or in intermittent light source on events (where the narrow wavelength light source 18 is turned on an off while the fabric substrate 20 is positioned relative to the narrow wavelength light source 18. In this single pass printing system 10, printing and selective heating of the pigment in the printed ink are each performed as the fabric substrate 20 is within proximity of the respective printer component.

As shown in FIG. 3A, some examples of the printing system 10 further include the inkjet printhead 14, which contains and dispenses the pre-treatment composition 28. In this example, inkjet printhead 14 is a pagewide printhead that is in a fixed position relative to the fabric substrate 20. When the fabric substrate 20 is moved relative to the inkjet printhead 14, an example of the pre-treatment composition 28 disclosed herein is inkjet printed directly onto fabric substrate 20. The fabric substrate 20 is then moved to be exposed to printing and selective heating, While not shown, it is to be understood that the inkjet printhead 14 could be replaced with a mechanism that will apply the pre-treatment composition 28 in accordance with an analog method. The mechanism could be an in-line or off-line sprayer, roll coater, etc. Also while not shown, a dryer may be positioned between the printheads 14 and 12 to dry the pre-treatment composition before the thermally curable inkjet ink is applied thereon.

The single pass printing and selective heating performed using the printing system 10 results in the printed article 30 on the fabric substrate 20. The heat absorbed by the pigment is sufficient to bind the pigment onto the fabric substrate 20. The heat to initiate fixation may range from about 100° C. to about 200° C.

In the example system 10′ shown in FIG. 3B, the textile fabric/fabric substrate 20 may be transported through the printing system 10′ along the path shown by the arrow 22′. In this example, printhead(s) 12′ is attached to a carriage (not shown) or other mechanism that moves the printhead 12′ relative to the fabric substrate 20 in the path shown by the arrow 32. When the printhead(s) 12′ is/are moved relative to the fabric substrate 20, a single color or multiple colors of the thermally curable ink composition 24 is/are inkjet printed directly onto fabric substrate 20 by the printhead(s) 12′ to form an ink layer. The color(s), amount(s), and arrangement of the thermally curable ink composition(s) 24 that is/are applied depend upon the digital image from which the print is being generated. In this example, the total desired amount of thermally curable ink composition(s) 24 that is dispensed takes place over multiple passes of the printhead(s) 12′.

Exposure to the UV and/or IR radiation may occur after the multiple printing passes, or between each of the multiple printing passes. In this example, the narrow wavelength light source 18′ is attached to a carriage (not shown) or other mechanism that moves the narrow wavelength light source 18′ relative to the fabric substrate 20 in the path shown by the arrow 32. As discussed in reference to the methods 100, 200, the total exposure time is 3 seconds or less, whether exposure takes place in a single pass or multiple passes.

As shown in FIG. 3B, some examples of the printing system 10′ further include the inkjet printhead 14′, which contains and dispenses the pre-treatment composition 28. In this example, inkjet printhead 14′ is a printhead that is attached to a carriage (not shown) or other mechanism that moves the printhead 14′ relative to the fabric substrate 20 in the path shown by the arrow 32. When the fabric substrate 20 is moved relative to the inkjet printhead 14′, an example of the pre-treatment composition 28 disclosed herein is inkjet printed directly onto fabric substrate 20. The printhead 12′ and the narrow wavelength radiation source 18′ are then moved to print and selectively heat. While not shown, it is to be understood that the inkjet printhead 14′ could be replaced with a mechanism that will apply the pre-treatment composition 28 in accordance with an analog method. The mechanism could be an in-line or off-line sprayer, roll coater, etc.

The multiple pass printing and single or multiple pass selective heating performed using the printing system 10′ results in the printed article 30 on the fabric substrate 20. The heat absorbed by the pigment is sufficient to bind the pigment onto the fabric substrate 20. The heat to initiate fixation may range from about 100° C. to about 200° C.

To further illustrate the present disclosure, examples are given herein. It is to be understood that these examples are provided for illustrative purposes and are not to be construed as limiting the scope of the present disclosure.

EXAMPLES Example 1

In this example, several example print swaths, comparative print swaths, and control print swaths were generated.

The fabric substrates used were cotton and nylon. A pre-treatment composition, a cyan thermally curable ink, and a black thermally curable ink were used. The pre-treatment composition is shown in Table 1 and the cyan and black thermally curable ink compositions are shown in Table 2.

TABLE 1 Pre-Treatment Composition Ingredient Wt Type Specific Ingredient % Solvent Tetraethylene glycol 12 Surfactant SURFYNOL ® SEF 0.07 (Evonik Ind.) Fixing Agent Calcium nitrate tetrahydrate 10 Chelating TIRON ™ monohydrate 0.1 Agent Antimicrobial ACTICIDE ® B20 0.04 (Thor Chemicals) Water Balance

TABLE 2 Thermally Curable Ink Compositions Ingredient Specific Black Ink Cyan Ink Type Ingredient (wt %) (wt %) UV absorbing carbon black 2.75 N/A Pigment cyan (PB15:3) N/A 2.5 Dispersion Binder IMPRANIL ® DLN-SD 6 6 Solvent Glycerol 8 8 Surfactant SURYNOL ® 440 0.3 0.3 Anti-Kogation CRODAFOS ™ N-3A 0.5 0.5 Agent Anti-Decel Agent LIPONIC ® EG-1 1 1 Antimicrobial ACTICIDE ® B20 0.044 0.044 (Thor Chemicals) Water Balance Balance

To prepare the print swaths, 1 drop per pixel of the pre-treatment composition was printed on the respective fabric substrates, and 3 drops per pixel of either the black ink or the cyan ink was printed on the pre-treatment composition. The inks were printed in two passes −½ of the ink in the first pass and ½ of the ink in the other pass.

For some of the example print swaths, a 395 nm light emitting diode (Hereaus lamp) was used. When operated at 50% power, the light source emitted 6.62 W/cm². The example print swaths on the cotton fabric were exposed to 6 exposures of 500 msec each, with a total energy of 19.87 J/cm². The example print swaths on the nylon fabric were exposed to 2 exposures of 100 msec each, with a total energy of 1.32 J/cm². On the nylon fabric, UV radiation exposure took place after each of the ink passes.

For some the comparative print swaths, a heat press alone was used. The comparative print swaths were exposed to 150° C. for 3 minutes using the heat press.

For some other comparative print swaths, both LED exposure and heat press exposure were.

For the control print swaths, no heating was used. These print swaths were allowed to air dry.

After printing and the various drying techniques were performed, each of the example print swaths, comparative example print swaths, and the control print swaths was washed 5 times in a Kenmore 90 Series Washer (Model 110.289 227 91) with warm water (at about 40° C.) and detergent. Each print was allowed to air dry between each wash.

Photographs were taken of the swaths after washing to visibly compare the washfastness of the control, example, and comparative examples swaths. The results, which are reproduced in black and white, are shown in FIGS. 4 through 7. To easily compare the control, example, and comparative example print swaths, a control swath was generated next to an example swath, and another example swath was generated next to a comparative example swath. Table 3 provides a key for FIGS. 4 and 5, which show the various swaths printed on cotton. Table 4 provides a key for FIGS. 6 and 7, which show the various swaths printed on nylon.

TABLE 3 Cotton Black Ink Cyan Ink FIG. # Control LED Heat Press Control LED Heat Press 4 C1 E1 and CE2 and N/A N/A N/A CE2 CE1 5 N/A N/A N/A C2 E2 and CE4 and CE4 CE3

TABLE 4 Nylon Black Ink Cyan Ink FIG. # Control LED Heat Press Control LED Heat Press 6 C3 E3 and CE6 and N/A N/A N/A CE6 CE5 7 N/A N/A N/A C4 E4 and CE8 and CE8 CE7

As depicted in FIG. 4, the black example print swath E1 printed on cotton and exposed to LED heating exhibited much better washfastness than the control black C1, and exhibited slightly better washfastness than the black comparative example print swath CE1 printed on cotton and exposed to the heat press and the black comparative example print swath CE2 printed on cotton and exposed to both LED and the heat press.

As depicted in FIG. 5, the cyan example print swath E2 printed on cotton and exposed to LED heating exhibited much better washfastness than the control cyan C2, and exhibited slightly better washfastness than the cyan comparative example print swath CE3 printed on cotton and exposed to the heat press and the cyan comparative example print swath CE4 printed on cotton and exposed to both LED and the heat press.

As depicted in FIG. 6, the black example print swath E3 printed on nylon and exposed to LED heating exhibited much better washfastness than the control black C3, and exhibited comparable or slightly better washfastness than the black comparative example print swath CE5 printed on nylon and exposed to the heat press and the black comparative example print swath CE6 printed on nylon and exposed to both LED and the heat press.

As depicted in FIG. 7, the cyan example print swath E4 printed on nylon and exposed to LED heating exhibited much better washfastness than the control cyan C4, and exhibited comparable or slightly better washfastness than the cyan comparative example print swath CE7 printed on nylon and exposed to the heat press and the cyan comparative example print swath CE8 printed on nylon and exposed to both LED and the heat press.

After printing, the initial optical density of each example swath, control swath and comparative swath exposed to the heat press alone was measured. The optical density of each print swath was again measured after washing. The change in optical density (Δ OD) was calculated for each print swath. The results are shown in FIG. 8. The change in optical density was less for each of the example swaths (E1-E4), which confirms the conclusions made based on the photographs.

Overall, the results in this example illustrate that LED exposure forms prints with improved washfastness on both cotton and nylon, when compared to prints formed with no heating or with heat press heating. LED exposure also speeds up the printing process, comparing. e.g., 3 minutes with the heat press versus 0.2 seconds or 3 seconds with the LED lamp.

Example 2

Twelve examples of the thermally curable ink composition disclosed herein were prepared.

The example binder included in four of the example ink compositions (referred to as “example 1 black,” “example 1 cyan,” “example 1 magenta,” and “example 1 yellow”) was IMPRANIL® DLN-SD (an anionic aliphatic polyester-polyurethane binder, CAS #375390-41-3; Mw 45,000 Mw; Acid Number 5.2; Tg −47° C.; Melting Point 175-200° C.) from Covestro. The general formulation of these four example ink compositions is shown in Table 4, with the wt % active of each component that was used. For example, the weight percentage of the pigment dispersion represents the total pigment solids (i.e., wt % active pigment) present in the final ink formulations. In other words, the amount of the pigment dispersion added to the example ink compositions was enough to achieve a pigment solids level equal to the given weight percent. Similarly, the weight percentage of the binder represents the total binder solids (i.e., wt % active binder) present in the final ink formulations. Additionally, a 5 wt % potassium hydroxide aqueous solution was added to each of the example ink compositions until a pH of about 8.5 was achieved.

TABLE 5 Example Example Example Example 1 1 1 1 Specific black cyan magenta yellow Ingredient Component (wt %) (wt %) (wt %) (wt %) Pigment Black 2.5 — — — dispersion pigment dispersion Cyan — 2.5 — — pigment dispersion Magenta — — 3 — pigment dispersion Yellow — — — 3 pigment dispersion Binder IMPRANIL ® 6 6 6 6 DLN-SD Co-solvent Glycerol 8 8 8 8 Anti-decel LIPONIC ® 1 1 1 1 agent EG-1 Anti- CRODAFOS ™ 0.5 0.5 0.5 0.5 kogation N-3A agent Surfactant SURFYNOL ® 0.3 0.3 0.3 0.3 440 Biocide ACTICIDE ® 0.044 0.044 0.044 0.044 B20 Water Deionized Balance Balance Balance Balance water

The example binder included in another four of the example ink compositions (referred to as “example 2 black,” “example 2 cyan,” “example 2 magenta,” and “example 2 yellow”) was a latex polymer binder. The general formulation of these four example ink compositions is shown in Table 6, with the wt % active of each component that was used.

TABLE 6 Example Example Example Example 2 2 2 2 Specific black cyan magenta yellow Ingredient Component (wt %) (wt %) (wt %) (wt %) Pigment Black ~2 — — — dispersion pigment dispersion Cyan — ~1.5 — — pigment dispersion Magenta — — ~3 — pigment dispersion Yellow — — — ~3 pigment dispersion Binder Latex polymer 7 7 7 7 Co- 2-pyrrolidone 13 13 13 13 solvent 2-methyl-1,3- 9 9 9 9 propanediol Chelating TRILON ® 0.04 0.04 0.04 0.04 agent M Anti- CRODAFOS ™ 0.2 0.2 0.2 0.2 kogation N-3A agent Surfactant TERGITOL ® 0.5 0.5 0.5 0.5 15-S-7 TERGITOL ® 0.9 0.9 0.9 0.9 TMN-6 CAPSTONE ® 0.65 0.65 0.65 0.65 FS-35 Wax Filled wax 0.8 0.8 0.8 0.8 Biocide ACTICIDE ® 0.04 0.04 0.04 0.04 B20 Water Deionized Balance Balance Balance Balance water

The example binder included in the last four of the example ink compositions (referred to as “example 3 black,” “example 3 cyan,” “example 3 magenta,” and “example 3 yellow”) was another type of latex polymer binder. The general formulation of these four example ink compositions is shown in Table 7, with the wt % active of each component that was used.

TABLE 7 Example Example Example Example 3 3 3 3 Specific black cyan magenta yellow Ingredient Component (wt %) (wt %) (wt %) (wt %) Pigment Black ~2.5 — — — dispersion pigment dispersion Cyan — ~1.5 — — pigment dispersion Magenta — — ~3.5 — pigment dispersion Yellow — — — ~3.5 pigment dispersion Binder Latex polymer 10 10 10 10 Co- 1,2-butanediol 18 18 18 18 solvent 2-pyrrolidone 3 3 3 3 Tripropylene 2 2 2 2 glycol methyl ether Anti- CRODAFOS ™ 0.35 0.35 0.35 0.35 kogation O3A agent Surfactant TERGITOL ® 0.2 0.2 0.2 0.2 15-S-7 CAPSTONE ® 0.4 0.4 0.4 0.4 FS-35 Water Deionized Balance Balance Balance Balance water

Several prints were generated by thermal inkjet printing using the example ink compositions. For each print, the amount of the example ink composition printed was 20 gsm. The prints were generated on cotton. No pre-treatment was performed on the fabric before generating the prints.

The post-treatment that was performed on each region of a first set of prints is schematically shown in FIG. 9. For these prints, there were two control regions and an example region. In the control regions (at the left and right of each print), no post-treatment or curing was performed (this region is labeled “untreated control” in FIGS. 9-12 and Tables 8 and 9). In the example region (at the middle of each print), the print was exposed to ultraviolet light for 1 second from a 395 nm light emitting diode operated at 50% energy (this region is labeled “LED exposed” in FIG. 9 and Tables 8 and 9 and “LED395, 50% energy, 1 sec” in FIGS. 10A, 11A, and 12A). When operated at 50% power, the light source emitted 6.62 W/cm². The post-treatment that was performed on a second set of prints involved exposure to the heat press at 150° C. for about 3 minutes.

Optical Density

The initial optical density (initial OD) of each region of each print in the first set of prints was measured. The initial optical density (initial OD) of each print in the second set of prints was also measured. Then, the prints in each set were washed 5 times in a Kenmore 90 Series Washer (Model 110.289 227 91) with warm water (at about 40° C.) and detergent. Each print was allowed to air dry between each wash. Then, the optical density (OD after 5 washes) of each region of each print in the first set of prints and of each print in the second set of prints was measured, and the percent change in optical density (%Δ OD) was calculated for each region and print.

The initial optical density (initial OD), the optical density after 5 washes (OD after 5 washes), and the percent change in optical density (%Δ in OD) of each region and print are shown in Table 8. In Table 8, each region or print is identified by the example ink composition, and the post-treatment (if any) used to generate the region or print.

TABLE 8 (Cotton) Post-treatment used to generate Ink composition used the region/ Initial OD after % Δ to generate the print print OD 5 washes in OD Example 1 black Untreated control 1.121 0.798 −28.8 Example 1 cyan Untreated control 1.053 0.777 −26.2 Example 1 magenta Untreated control 1.010 0.679 −32.8 Example 1 yellow Untreated control 1.092 0.645 −41.0 Example 2 black Untreated control 1.053 0.442 −58.1 Example 2 cyan Untreated control 0.959 0.177 −81.6 Example 2 magenta Untreated control 0.953 0.263 −72.5 Example 2 yellow Untreated control 0.931 0.115 −87.6 Example 3 black Untreated control 1.156 0.559 −51.7 Example 3 cyan Untreated control 1.034 0.359 −65.3 Example 3 magenta Untreated control 1.040 0.382 −63.3 Example 3 yellow Untreated control 0.988 0.339 −65.7 Example 1 black LED exposed 1.159 1.080 −6.8 Example 1 cyan LED exposed 1.072 0.897 −16.4 Example 1 magenta LED exposed 1.044 0.874 −16.3 Example 1 yellow LED exposed 1.001 0.834 −16.6 Example 2 black LED exposed 1.125 1.029 −8.5 Example 2 cyan LED exposed 1.035 0.913 −11.8 Example 2 magenta LED exposed 0.996 0.871 −12.6 Example 2 yellow LED exposed 1.017 0.898 −11.7 Example 3 black LED exposed 1.194 1.035 −13.3 Example 3 cyan LED exposed 1.062 0.880 −17.1 Example 3 magenta LED exposed 1.097 0.949 −13.5 Example 3 yellow LED exposed 1.089 0.930 −14.6 Example 1 black Heat press 1.153 1.008 −12.6 Example 1 cyan Heat press 1.104 1.013 −8.3 Example 1 magenta Heat press 0.977 0.898 −8.1 Example 1 yellow Heat press 1.025 0.902 −12.0 Example 2 black Heat press 1.070 0.864 −19.2 Example 2 cyan Heat press 0.998 0.812 −18.6 Example 2 magenta Heat press 0.956 0.782 −18.2 Example 2 yellow Heat press 0.965 0.778 −19.3 Example 3 black Heat press 1.107 0.870 −21.5 Example 3 cyan Heat press 1.005 0.799 −20.5 Example 3 magenta Heat press 1.053 0.783 −25.7 Example 3 yellow Heat press 1.023 0.688 −32.8

As shown in Table 8, the regions of the prints in the first set of prints exposed to ultraviolet light had a change in optical density of at least 37% less than the change in optical density of the regions of the same print that was untreated (i.e., the control). These results indicate that the prints generated on cotton with an example ink composition and exposed to 395 nm ultraviolet light from an LED for 1 second have higher optical density than prints generated on cotton with the example ink composition and without any post-treatment.

As also shown in Table 8, for the prints generated with the “example 2” ink compositions, the regions of the prints exposed to ultraviolet light had a change in optical density of at least 30% less than the change in optical density of the same color prints that were exposed to the heat press at 150° C. for 3 minutes. Table 8 further shows, for the prints generated with the “example 3” ink compositions, that the regions of the prints exposed to ultraviolet light had a change in optical density of at least 16.5% less than the change in optical density of the same color prints that were exposed to the heat press at 150° C. for 3 minutes. These results indicate that the prints generated on cotton with an “example 2” ink composition or “example 3” ink composition and exposed to 395 nm ultraviolet light from an LED for 1 second have higher optical density than prints generated on cotton with an “example 2” ink composition or “example 3” ink composition and exposed to a heat press at 150° C. for 3 minutes.

Washfastness

The prints were also tested for washfastness. The L*a*b* values of a color (e.g., cyan, magenta, yellow, black, red, green, blue, white) before and after the 5 washes were measured. L* is lightness, a* is the color channel for color opponents green-red, and b* is the color channel for color opponents blue-yellow. The color change was then calculated using both the CIEDE1976 color-difference formula and the CIEDE2000 color-difference formula.

The CIEDE1976 color-difference formula is based on the CIELAB color space. Given a pair of color values in CIELAB space L*₁,a*₁,b*₁ and L*₂,a*₂,b*₂, the CIEDE1976 color difference between them is as follows:

ΔE ₇₆=√{square root over ([(L* ₂ −L* ₁)²+(a* ₂ −a* ₁)²+(b* ₂ −b* ₁)²])}

It is noted that ΔE₇₆ is the commonly accepted notation for CIEDE1976.

The CIEDE2000 color-difference formula is based on the CIELAB color space. Given a pair of color values in CIELAB space L*₁,a*₁,b*₁ and L*₂,a*₂,b*₂, the CIEDE2000 color difference between them is as follows:

ΔE ₀₀(L* ₁ ,a* ₁ ,b* ₁ ; L* ₂ ,a* ₂ ,b* ₂)=ΔE ₀₀ ¹² =ΔE ₀₀  (1)

It is noted that ΔE₀₀ is the commonly accepted notation for CIEDE2000.

Given two CIELAB color values {L*_(i),a*_(i),b*_(i)}_(i=1) ² and parametric weighting factors k_(L), k_(C), k_(H), the process of computation of the color difference is summarized in the following equations, grouped as three main parts.

1. Calculate C′_(i),h′_(i):

$\begin{matrix} {{{C_{i,{ab}}^{*}\sqrt{\left( {\left( a_{i}^{*} \right)^{2} + \left( b_{i}^{*} \right)^{2}} \right),}i} = 1},2} & (2) \\ {{\overset{\_}{C}}_{ab}^{*} = \frac{C_{1,{ab}}^{*} + C_{2,{ab}}^{*}}{2}} & (3) \\ {G = {0.5\left( {1 - \sqrt{\left( \frac{{\overset{\_}{C}}_{ab}^{*7}}{{\overset{\_}{C}}_{ab}^{*7} + 25^{7}} \right)}} \right)}} & (4) \\ {{a_{i}^{\prime} = {\left( {1 + G} \right)a_{i}^{*}}},{i = 1},2} & (5) \\ {{C_{i}^{\prime} = {{\sqrt{\left( {\left( a_{i}^{\prime} \right)^{2} + \left( b_{i}^{\prime} \right)^{2}} \right),}i} = 1}},2} & (6) \\ {h_{i}^{\prime} = \left\{ {\begin{matrix} 0 & {b_{i}^{*} = {a_{i}^{\prime} = 0}} \\ {\tan^{- 1}\left( {b_{i}^{*},a_{i}^{\prime}} \right)} & {otherwise} \end{matrix},{i = 1},2} \right.} & (7) \end{matrix}$

2. Calculate ΔL′, ΔC′,ΔH′:

$\begin{matrix} {{\Delta\; L^{\prime}} = {L_{2}^{*} - L_{1}^{*}}} & (8) \\ {{\Delta\; C^{\prime}} = {C_{2}^{*} - C_{1}^{*}}} & (9) \\ {{\Delta\; h^{\prime}} = \left\{ \begin{matrix} 0 & {{C_{1}^{\prime}C_{2}^{\prime}} = 0} \\ {h_{2}^{\prime} - h_{1}^{\prime}} & {{{C_{1}^{\prime}C_{2}^{\prime}} \neq 0};{{{h_{2}^{\prime} - h_{1}^{\prime}}} \leq 180^{\circ}}} \\ {\left( {h_{2}^{\prime} - h_{1}^{\prime}} \right) - 360} & {{{C_{1}^{\prime}C_{2}^{\prime}} \neq 0};{{{h_{2}^{\prime} - h_{1}^{\prime}}} > 180^{\circ}}} \\ {\left( {h_{2}^{\prime} - h_{1}^{\prime}} \right) + 360} & {{{C_{1}^{\prime}C_{2}^{\prime}} \neq 0};{{{h_{2}^{\prime} - h_{1}^{\prime}}} < {`180}^{\circ}}} \end{matrix} \right.} & (10) \\ {{\Delta\; H^{\prime}} = {2\sqrt{C_{1}^{\prime}C_{2}^{\prime}}{\sin\left( \frac{\Delta\; h^{\prime}}{2} \right)}}} & (11) \end{matrix}$

3. Calculate CIEDE2000 color-difference ΔE₀₀:

$\begin{matrix} {\mspace{79mu}{{\overset{\_}{L}}^{\prime} = {\left( {L_{1}^{*} + L_{2}^{*}} \right)/2}}} & (12) \\ {\mspace{79mu}{{\overset{\_}{C}}^{\prime} = {\left( {C_{1}^{*} + C_{2}^{*}} \right)/2}}} & (13) \\ {{\overset{\_}{h}}^{\prime} = \left\{ \begin{matrix} \frac{h_{1}^{\prime} + h_{2}^{\prime}}{2} & {{{{h_{1}^{\prime} - h_{2}^{\prime}}} \leq 180^{\circ}};{{C_{1}^{\prime}C_{2}^{\prime}} \neq 0}} \\ \frac{h_{1}^{\prime} + h_{2}^{\prime} + 360^{\circ}}{2} & {{{{h_{1}^{\prime} - h_{2}^{\prime}}} > 180^{\circ}};{\left( {h_{1}^{\prime} + h_{2}^{\prime}} \right) < 360^{\circ}};{{C_{1}^{\prime}C_{2}^{\prime}} \neq 0}} \\ \frac{h_{1}^{\prime} + h_{2}^{\prime} - 360^{\circ}}{2} & {{{{h_{1}^{\prime} - h_{2}^{\prime}}} > 180^{\circ}};{\left( {h_{1}^{\prime} + h_{2}^{\prime}} \right) \geq 360^{\circ}};{{C_{1}^{\prime}C_{2}^{\prime}} \neq 0}} \\ \left( {h_{1}^{\prime} + h_{2}^{\prime}} \right) & {{C_{1}^{\prime}C_{2}^{\prime}} = 0} \end{matrix} \right.} & (14) \\ {T = {1 - {0.17{\cos\left( {{\overset{\_}{h}}^{\prime} - 30^{\circ}} \right)}} + {0.24{\cos\left( {2{\overset{\_}{h}}^{\prime}} \right)}} + {0.32{\cos\left( {{3{\overset{\_}{h}}^{\prime}} + 6^{\circ}} \right)}} - {0.20{\cos\left( {{4{\overset{\_}{h}}^{\prime}} - 63^{\circ}} \right)}}}} & (15) \\ {\mspace{79mu}{{\Delta\theta} = {30\exp\left\{ {- \left\lbrack \frac{{\overset{\_}{h}}^{\prime} - 275^{\circ}}{25} \right\rbrack^{2}} \right\}}}} & (16) \\ {\mspace{79mu}{R_{c} = {2\sqrt{\left( \frac{{\overset{\_}{C}}^{\prime 7}}{{\overset{\_}{C}}^{\prime 7} + 25^{7}} \right)}}}} & (17) \\ {\mspace{79mu}{S_{L} = {1 + \frac{0.015\left( {{\overset{\_}{L}}^{\prime} - 50} \right)^{2}}{\sqrt{\left( {20 + \left( {{\overset{\_}{L}}^{\prime} - 50} \right)^{2}} \right)}}}}} & (18) \\ {\mspace{79mu}{S_{C} = {1 + {0.045{\overset{\_}{C}}^{\prime}}}}} & (19) \\ {\mspace{79mu}{S_{H} = {1 + {0.015{\overset{\_}{C}}^{\prime}T}}}} & (20) \\ {\mspace{79mu}{R_{T} = {{- {\sin\left( {2{\Delta\theta}} \right)}}R_{C}}}} & (21) \\ {{\Delta\; E_{00}^{12}} = {{\Delta\;{E_{00}\left( {L_{1}^{*},a_{1}^{*},{b_{1}^{*};L_{2}^{*};L_{2}^{*}},a_{2}^{*},b_{2}^{*}} \right)}} = \sqrt{\left( {\left( \frac{\Delta\; L^{\prime}}{k_{L}S_{L}} \right)^{2} + \left( \frac{\Delta\; C^{\prime}}{k_{C}S_{C}} \right)^{2} + \left( \frac{\Delta\; H^{\prime}}{k_{H}S_{H}} \right)^{2} + {{R_{T}\left( \frac{\Delta\; C^{\prime}}{k_{C}S_{C}} \right)}\left( \frac{\Delta\; H^{\prime}}{k_{H}S_{H}} \right)}} \right)}}} & (22) \end{matrix}$

The results of the ΔE₇₆ calculations and the ΔE₀₀ calculations for each region of each print generated are shown in Table 9. In Table 9, each region or print is identified by the example ink composition, and the post-treatment (if any) used to generate the region or print.

TABLE 9 (Cotton) Ink composition used Post-treatment used to generate the print to generate the print ΔE₇₆ ΔE₀₀ Example 1 black Untreated control 13.59 11.88 Example 1 cyan Untreated control 10.98 7.16 Example 1 magenta Untreated control 14.40 7.49 Example 1 yellow Untreated control 26.60 6.18 Example 2 black Untreated control 31.30 31.10 Example 2 cyan Untreated control 46.10 28.26 Example 2 magenta Untreated control 45.68 27.06 Example 2 yellow Untreated control 62.60 22.74 Example 3 black Untreated control 28.80 27.67 Example 3 cyan Untreated control 32.15 20.88 Example 3 magenta Untreated control 35.70 21.68 Example 3 yellow Untreated control 43.64 13.53 Example 1 black LED exposed 3.44 2.95 Example 1 cyan LED exposed 6.13 3.97 Example 1 magenta LED exposed 6.97 3.29 Example 1 yellow LED exposed 4.96 1.18 Example 2 black LED exposed 4.43 3.89 Example 2 cyan LED exposed 6.60 4.35 Example 2 magenta LED exposed 6.45 4.80 Example 2 yellow LED exposed 3.81 2.27 Example 3 black LED exposed 6.38 5.40 Example 3 cyan LED exposed 7.16 5.43 Example 3 magenta LED exposed 7.08 4.95 Example 3 yellow LED exposed 5.13 2.22 Example 1 black Heat press 6.05 5.09 Example 1 cyan Heat press 3.78 2.50 Example 1 magenta Heat press 4.10 1.74 Example 1 yellow Heat press 8.26 1.83 Example 2 black Heat press 9.06 7.95 Example 2 cyan Heat press 6.24 4.77 Example 2 magenta Heat press 8.79 4.64 Example 2 yellow Heat press 10.45 2.65 Example 3 black Heat press 11.17 9.70 Example 3 cyan Heat press 6.45 4.76 Example 3 magenta Heat press 13.21 7.43 Example 3 yellow Heat press 18.39 4.57

As shown in Table 9, the ΔE₇₆ value and the ΔE₀₀ value of the regions of the prints exposed to ultraviolet light were at least 44% less than, respectively, the ΔE₇₆ value and the ΔE₀₀ value of the region of the same print that was untreated (i.e., the control prints). These results indicate that the prints generated on cotton with an example ink composition and exposed to 395 nm ultraviolet light with an LED for 1 second have better washfastness than prints generated on cotton with the example ink compositions without any post-treatment.

As also shown in Table 9, for the prints generated with the “example 2” ink compositions, the ΔE₇₆ value of the regions of the prints exposed to ultraviolet light were at least 26% less than the ΔE₇₆ value of the same color print that was exposed to the heat press at 150° C. for 3 minutes. Table 9 further shows, for the prints generated with the “example 2” ink compositions, the ΔE₀₀ value of the regions of the prints exposed to ultraviolet light were less than or comparable to the ΔE₀₀ value of the region of the same color print that was exposed to the heat press at 150° C. for 3 minutes. Still further, Table 9 shows, for the prints generated with the “example 3” ink compositions, the ΔE₇₆ value and the ΔE₀₀ value of the regions of the prints exposed to ultraviolet light were less than or comparable to, respectively, the ΔE₇₆ value and the ΔE₀₀ value of the same color print that was exposed to the heat press at 150° C. for 3 minutes. These results indicate that the prints generated on cotton with an “example 2” ink composition or “example 3” ink composition and exposed to 395 nm ultraviolet light from an LED for 1 second have better washfastness than prints generated on cotton with an “example 2” ink composition or “example 3” ink composition and exposed to the heat press at 150° C. for 3 minutes.

Color photographs of each of the prints generated in this example were taken before and after washing. The before and after photographs for the prints with the untreated control and example regions are reproduced in black and white in FIGS. 10A, 11A, and 12A, and the before and after photographs for the comparative prints exposed to the heat press are reproduced in black and white in FIGS. 10B, 11B, and 12B. Specifically, FIGS. 10A and 10B show the prints formed with the example 1 inks, FIGS. 11A and 11B show the prints formed with the example 2 inks, and FIGS. 12A and 12B show the prints formed with the example 3 inks. The labeling in FIGS. 10A, 11A, and 12A follows the schematic in FIG. 9. These results clearly that the regions of the prints exposed to 395 nm ultraviolet light exhibit better or comparable washfastness than the untreated control regions.

It is to be understood that the ranges provided herein include the stated range and any value or sub-range within the stated range, as if such values or sub-ranges were explicitly recited. For example, from about 2 wt % to about 15 wt % should be interpreted to include not only the explicitly recited limits of from about 2 wt % to about 15 wt %, but also to include individual values, such as about 2.35 wt %, about 3.5 wt %, about 10 wt %, about 13.5 wt %, etc., and sub-ranges, such as from about 2.5 wt % to about 14 wt %, from about 4.5 wt % to about 12.5 wt %, etc. Furthermore, when “about” is utilized to describe a value, this is meant to encompass minor variations (up to +/−10%) from the stated value.

Reference throughout the specification to “one example”, “another example”, “an example”, and so forth, means that a particular element (e.g., feature, structure, and/or characteristic) described in connection with the example is included in at least one example described herein, and may or may not be present in other examples. In addition, it is to be understood that the described elements for any example may be combined in any suitable manner in the various examples unless the context clearly dictates otherwise.

In describing and claiming the examples disclosed herein, the singular forms “a”, “an”, and “the” include plural referents unless the context clearly dictates otherwise.

While several examples have been described in detail, it is to be understood that the disclosed examples may be modified. Therefore, the foregoing description is to be considered non-limiting. 

What is claimed is:
 1. A textile printing method, comprising: applying a thermally curable ink composition on a fabric substrate, the thermally curable ink composition including: from about 1 wt % active to about 6 wt % active of a pigment that absorbs ultraviolet radiation, infrared radiation, or combinations thereof, based on a total weight of the thermally curable ink composition; from about 2 wt % active to about 20 wt % active of a polymeric binder, based on the total weight of the thermally curable ink composition; and an aqueous ink vehicle; and selectively heating the pigment of the thermally curable ink composition applied on the fabric substrate by exposing the fabric substrate to an emission wavelength from a narrow wavelength light source for a total exposure time of 3 seconds or less, thereby thermally fixing the pigment to the fabric substrate.
 2. The textile printing method as defined in claim 1 wherein the narrow wavelength light source is a light emitting diode that emits emission wavelengths ranging from about 365 nm to about 400 nm.
 3. The textile printing method as defined in claim 1, further comprising setting the narrow wavelength light source so that energy exposure ranges from about 2 J/cm² to about 28 J/cm².
 4. The textile printing method as defined in claim 1 wherein: the applying of the thermally curable ink composition is accomplished in multiple print passes; and the method further comprises exposing the fabric substrate to the emission wavelength from the narrow wavelength light source after each print pass for a time less than the total exposure time.
 5. The textile printing method as defined in claim 4 wherein the time for exposing the fabric substrate to the emission wavelength from the narrow wavelength light source after each print pass ranges from about 0.1 second to about 1 second.
 6. The textile printing method as defined in claim 1 wherein: the application of the thermally curable ink composition occurs prior to the selectively heating; and the selectively heating involves intermittent light source on events and light source off events.
 7. The textile printing method as defined in claim 1, further comprising warming or cooling the fabric substrate having the thermally curable ink composition thereon at a temperature below a fixation temperature of the thermally curable ink composition: i) before the selectively heating; or ii) concurrently with the selectively heating; or iii) both before and concurrently with the selectively heating.
 8. The textile printing method as defined in claim 1 wherein the polymeric binder in the thermally curable ink composition is selected from the group consisting of a polyester-polyurethane binder, a polyether-polyurethane binder, a polycarbonate-polyurethane binder, a latex binder, and combinations thereof.
 9. The textile printing method as defined in claim 1 wherein the fabric substrate is selected from the group consisting of cotton, a cotton blend, nylon, a nylon blend, polyester, a polyester blend, silk, a silk blend, spandex, a spandex blend, rayon, and a rayon blend.
 10. A textile printing method, comprising: applying a pre-treatment composition on a fabric substrate, the pre-treatment composition including: a fixing agent selected from the group consisting of a multivalent metal cation, a cationic polymer, and a combination of a multivalent metal cation and a cationic polymer; and an aqueous pre-treatment vehicle; applying a thermally curable ink composition on the fabric substrate, the thermally curable ink composition including: from about 1 wt % active to about 6 wt % active of a pigment that absorbs ultraviolet radiation, infrared radiation, or combinations thereof, based on a total weight of the thermally curable ink composition; from about 2 wt % active to about 20 wt % active of a polymeric binder, based on the total weight of the thermally curable ink composition; and an aqueous ink vehicle; and selectively heating the pigment of the thermally curable ink composition applied on the fabric substrate by exposing the fabric substrate to an emission wavelength from a narrow wavelength light source for a total exposure time of 3 seconds or less, thereby thermally fixing the pigment to the fabric substrate.
 11. The textile printing method as defined in claim 10 wherein the narrow wavelength light source is a light emitting diode that emits emission wavelengths ranging from about 365 nm to about 400 nm.
 12. The textile printing method as defined in claim 10, further comprising setting the narrow wavelength light source so that the energy exposure ranges from about 2 J/cm² to about 28 J/cm².
 13. The textile printing method as defined in claim 10 wherein: the application of the pre-treatment composition occurs prior to the application of the thermally curable ink composition; the applying of the thermally curable ink composition is accomplished in multiple print passes; and the method further comprises exposing the fabric substrate to the emission wavelength from the narrow wavelength light source after each print pass for a time less than the total exposure time.
 14. The textile printing method as defined in claim 10 wherein: the application of the pre-treatment composition occurs prior to the application of the thermally curable ink composition; the application of the thermally curable ink composition occurs prior to the selectively heating; and the selectively heating involves intermittent light source on events and light source off events.
 15. The textile printing method as defined in claim 10, further comprising warming or cooling the fabric substrate having the pre-treatment composition and the thermally curable ink composition thereon at a temperature below a fixation temperature of the thermally curable ink composition: i) before the selectively heating; or ii) concurrently with the selectively heating; or iii) both before and concurrently with the selectively heating. 